Multi-Ratio Transmission System with Parallel Vertical and Coaxial Planet Gears

ABSTRACT

A multi-ratio transmission system with parallel vertical and coaxial planet gears is provided, including: multiple planet gear sub-systems, a coupling assembly, a setting element, a setting element controller, an annular gear, a cylindrical casing, a sprocket and a central axle. The planet gear sub-systems are disposed coaxially in series along a first axis. Each of the planet gear sub-system includes a sun gear and at least one planet gear. The coupling assembly transmits the rotation between every two adjacent planet gear sub-systems. The setting element optionally engages with the sun gear. The annular gear is engaged to the planet gear and is installed onto a one-way clutch. The cylindrical casing encloses the planet gear sub-systems. The sprocket is installed onto the one-way clutch for connecting an external transmission system. The central axle enables the hollowed tube of the setting element controller to rotate around the central axle.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority of Taiwanese patent application No.101120938, filed on Jun. 11, 2012, which is incorporated herewith byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a multi-ratio transmissionsystem, more particularly, relates to a multi-ratio transmission systemwith parallel vertical and coaxial planet gears which can be used onbicycles, transportation vehicles or other devices.

2. The Prior Arts

Mechanical multi-ratio transmission systems are widely used in manydifferent kinds of power machineries and equipments. The main purpose ofthe mechanical multi-ratio transmission system is to provide the changein rotation speeds and torques between the input end and the output endof the machinery.

The bicycle derailleur is one of the commonly seen multi-ratiotransmission systems, which is mainly composed of different sizes ofsprockets. As shown in FIG. 1, the bicycle derailleur system 900includes multiple sprockets 902 which are coaxially disposed on thebicycle along bicycle wheel axle 904, e.g. the rear bicycle wheel axis.The sprockets 902 are connected to the bicycle pedals through a chain906. In the system as described above, derailing the chain 906 betweensprockets 902 of different sizes can change the rotation speed ratiobetween the rear bicycle wheel and the pedal. Due to the nature of thestructure of the derailleur, the axial size of the derailleur systemwould increase as more sprockets are added to the system. Therefore,only a limited number of sprockets can be used in such derailleur systemto prevent the size of the system from becoming too large and thusinterfering with the operation of the machinery or equipment. However,since each sprocket represents a different rotation speed, the number ofthe sprockets determines the number of transmission ratios available ina bicycle derailleur system. Hence, under the condition that the numberof sprockets is limited, the number of the transmission ratios that canbe provided by the derailleur is also limited.

Another type of commonly seen multi-ratio transmission system is thegear shifting system of the mobile vehicles, such as the ones in theautomobiles or motorcycles. As shown in FIG. 2, such gear shiftingsystem 920 usually have multiple sets of gears 924 that are engaged toone another installed within a metal casing 922. These gears 924 rotatearound axles that are separately disposed from one another, andoptionally slide on the axles to achieve different engagement status ofthe gears 924, thereby achieving the change in the speed ratio andtorque between the output end and the input end. The gears 924 and theaxles of the gears have the same size. In order to provide enough spacefor the gears to move around, the size of such gear shifting system isrelatively large. In addition, similar to the derailleur of the bicycle,the number of the transmission ratios that can be achieved is alsodetermined by the number of the gears in the system; therefore, when thenumber of gears is limited due to the limitation of the actual design ofsuch system, the number of the transmission ratios that can be providedis also limited.

On the other hand, planet gear system is an effective way to reduce thesize of the gear transmission system in the mechanical industry. FIG. 3is an example of a commonly seen planet gear system. As shown in FIG. 3,the planet gear system 940 includes a sun gear 942 and an annular gear944. The sun gear 942 and the annular gear 944 are coaxially placed witheach other to form an annular space within. Multiple planet gears 946are placed inside the annular space to simultaneously engage with thesun gear 942 and the annular gear 944. With such configuration, the sungear 942, the annular gear 944 and the planet gears 946 basically rotatein different speed. When the planet gear system as described above is inuse, each of the sun gear, the planet gear and the annular gear serve asthe input end or the output end to change the rotation speed and thetorque between the input end and the output end. However, the number oftransmission ratio that can be achieved by a single planet gear systemis limited; hence, two sets or more of the planet gear systems are oftencoupled together in the axial direction to increase the number of thetransmission ratio or torque available. In addition, the rotation axesof the planet gears are parallel to the rotation axis of the sun gear,which still result in the increase of the overall size of the system.

Furthermore, similar to the derailleur of the bicycle and the gearshifting system of the automobile or motorcycle, axially couplingmultiple planet gear systems together still increases the overall sizeof the multi-ratio transmission system, which is a disadvantage to theapplication of the system.

Therefore, it is urgently needed for the industry to develop a type ofthe multi-ratio transmission system that can provide a large number oftransmission ratios while maintaining an overall small size of thesystem.

SUMMARY OF THE INVENTION

A primary objective of the present invention is to provide a multi-ratiotransmission system with parallel vertical and coaxial planet gears. Themulti-ratio transmission system is featured by a large number of gearratios available with relatively small overall size of the system.

Another objective of the present invention is to provide a multi-ratiotransmission system with parallel vertical and coaxial planet gears,where the adjacent planet gear systems are driven by the difference inthe size of the coaxial pulleys, and by the combination relationshipbetween the coaxial sub-pulleys. With such configuration, the presentinvention can exceed the conventional multi-ratio transmission systembased on gears in the number of gear ratios available. In order toachieve a specific gear ratio in the conventional multi-ratiotransmission system, the section area of the system is likely toincrease; therefore the space needed for the system is also larger.Nevertheless, the combination relationship between the coaxial pulleyscan easily multiply the relative gear ratio, and the flexibility in thebelts can also provide the buffer effect needed during shifting betweendifferent gear ratios. In this way, a smooth shifting process isprovided without the jumps, which occur during the gear shifting, causedby the difference in the accelerations.

A further objective of the present invention is to provide a multi-ratiotransmission system with parallel vertical and coaxial planet gears,which has an overall size that can be installed onto a bicycle wheelaxle while providing a relatively more gear ratios available than theconventional bicycle derailleur system.

A further objective of the present invention is to provide a multi-ratiotransmission system with parallel vertical and coaxial planet gears,where the movement between the adjacent planet gear systems istransmitted through belts. With the flexibility of the belts, a buffereffect is achieved for smoothing the gear shifting process during thechange of speed when shifting between different gears ratios. In thisway, the riding experience of the bicycle can be enhanced due to theprevention of the jumps, which occurs during gear shifting, caused bythe difference in acceleration among different gear ratios.

A further objective of the present invention is to provide a multi-ratiotransmission system with parallel vertical and coaxial planet gearsincluding multiple planet gear sub-systems. The planet gear sub-systemsare coaxially placed with one another, and a coupling gear system isprovided to connect every two adjacent planet gear sub-systems to form ahybrid planet gear system. As a multi-ratio transmission system, suchhybrid planet gear system has a wider range of gear ratio available.

For achieving the foregoing objectives, the present invention provides amulti-ratio transmission system with parallel vertical and coaxialplanet gears. The multi-ratio transmission system includes: multipleplanet gear sub-systems, a coupling assembly, a setting element, asetting element controller, an annular gear, a cylindrical casing, asprocket and a central axle. The planet gear sub-systems are coaxiallydisposed in series along a first axis. Each of the planet gearsub-system includes: a sun gear and at least one planet gear. The sungear is coaxially disposed along the first axis and rotates around thefirst axis optionally. The planet gear is coaxially disposed along asecond axis, which is vertical to the first axis, and rotates around thesecond axis. The coupling assembly is disposed between every twoadjacent planet gear sub-systems so as to transmit the rotation of theplanet gear of the former planet gear sub-system to planet gear of thelatter planet gear sub-system between two adjacent planet gearsub-systems. The setting element is disposed corresponding to eachplanet gear sub-system. The setting element optionally moves in thedirection of first axis so as to optionally engage with the sun gear ofthe planet gear sub-system. The setting element controller has ahollowed tube, which is disposed coaxially with the first axis to rotatearound the first axis within a range of predetermined angles. Thehollowed tube has an outer circumferential surface. A cam groove isformed on the outer circumferential surface in the circumferentialdirection corresponding to each of the setting element of the planetgear sub-system, thereby allowing the setting element to optionally movealong the first axis and to optionally engage with the sun gears of theplanet gear sub-systems. The annular gear is engaged to the planet gearof at least one planet gear sub-system, and is installed onto a one-wayclutch. The cylindrical casing encloses the planet gear sub-systems,wherein the annular gear is secured at a front end of the cylindricalcasing. The sprocket is installed onto the one-way clutch. An externaltransmission system is installed with the sprocket to drive the planetgear sub-systems to rotate through the one-way clutch and the annulargear. The central axle is disposed coaxially with the first axis. Thecentral axle is inserted into a center through hole of the hollowed tubeof the setting element controller by relative rotation, thereby enablingthe hollowed tube to rotate around the central axle.

According to an embodiment of the present invention, the second axes ofthe planet gears of the planet gear sub-systems are configured to beparallel to one another.

According to an embodiment of the present invention, the sun gear ofeach planet gear sub-system includes an outer gear, which is a bevelgear. The planet gear of each planet gear sub-system is a bevel gear.The planet gear of each planet gear sub-system engages with the outergear of the sun gear.

According to an embodiment of the present invention, the sun gearfurther includes an inner gear. The setting element is a crown gear,which optionally engages with the inner gear of the sun gear.

According to an embodiment of the present invention, the sun gear ofeach planet gear sub-system includes an outer gear and an inner gear.The outer gear and the inner gear are coaxially connected to each other.The outer gear is located at the outer side of the inner gear and is abevel gear. The planet gear of the planet gear sub-system is a bevelgear, which is engaged with the outer gear of the sun gear. The settingelement is a crown gear, which optionally engages with the inner gear ofthe sun gear.

According to an embodiment of the present invention, each planet gearsub-system includes two planet gears, which are disposed opposite toeach other.

According to an embodiment of the present invention, the couplingassembly includes two pulleys and a belt. The coupling assembly isconnected to the planet gears of the two adjacent planet gearsub-systems respectively. The two pulleys are able to rotate insynchronization with the planet gears respectively. The belt is trainedaround the two pulleys so as to connect the two pulleys.

According to an embodiment of the present invention, the central axlehas two ends, which are secured with a bicycle rack respectively.

According to an embodiment of the present invention, two flat surfacesare formed opposite to each other on each end of the central axle. Thetwo flat surfaces of the central axle are engaged with two correspondingflat surfaces of the bicycle rack to prevent relative rotation betweenthe central axle and the bicycle rack.

According to an embodiment of the present invention, the setting elementcontroller further includes a rotation controller. The rotationcontroller is installed onto an end of the hollowed tube so as tooptionally rotate the hollowed tube in the range of predeterminedangles.

According to an embodiment of the present invention, the setting elementincludes a hollowed cylinder. Teeth are formed on a side end of thehollowed cylinder. The hollowed cylinder is disposed coaxially with thesun gear of the planet gear sub-system in such way that the hollowedcylinder moves along the first axis corresponding to the sun gear,thereby allowing the teeth to optionally engage with the sun gear. Thehollowed cylinder includes a control pin, in which a free end of thecontrol pin is inserted into the cam groove to move along the camgroove.

According to an embodiment of the present invention, wherein an outerthread is formed on a side circumferential surface of the annular gear,and an inner thread is formed on an inner circumferential surface of thecylindrical casing at a front end thereof. The inner thread is engagedwith the outer thread so as to secure the annular gear at the front endof the cylindrical casing.

According to an embodiment of the present invention, the multi-ratiotransmission system further includes another annular gear. The otherannular gear is secured at a rear end of the cylindrical casing oppositeto the front end. The annular gear and the other annular gear areengaged with the planet gear of a first and a last planet gearsub-systems in the planet gear sub-systems respectively. The first andthe last planet gear sub-systems further include a transmission gear,which is coaxially connected to the planet gear to engage with theannular gear.

According to an embodiment of the present invention, the other annulargear has an axial end. A flange is inwardly formed at the front end ofthe cylindrical casing. The annular gear is rotatably fitted inside therear end of the cylindrical casing by abutting the flange against theshoulder portion.

According to an embodiment of the present invention, wherein an outerthread is formed on a side circumferential surface of the annular gearengaging with the planet gear of the first planet gear sub-system. Aninner thread is formed on an inner circumferential surface of thecylindrical casing at a front end thereof. The inner thread is engagedwith the outer thread so as to secure the annular gear at the front endof the cylindrical casing.

According to an embodiment of the present invention, each planet gearsub-system includes an annular base. A circular wall structure is formedon the annular base surrounding the setting element and the planet gearof the planet gear sub-system while being disposed coaxially with thefirst axis. A hole is formed on the annular base for fitting andsupporting an axle of the planet gear.

According to an embodiment of the present invention, each annular baseof the planet gear sub-systems is formed with two axial ends, and theaxial ends of the annular bases are abutted against each other in thedirection of the first axis.

According to an embodiment of the present invention, at least one axialgroove is formed on an outer side surface of each annular base. Theaxial groove extends from one of the axial ends of the annular base toanother axial end thereof for tightly fitting a securing rod inside, soas to prevent relative rotation between annular bases.

According to an embodiment of the present invention, the rotationcontroller is installed onto a shift cable connector for connecting to ashift cable. The rotation controller and the hollowed tube installedonto the rotation controller are driven to rotate around the first axisby pulling the shift cable.

According to an embodiment of the present invention, a connecting holeis formed on the rotation controller for inserting an inner axial pin ofthe shift cable connector.

According to an embodiment of the present invention, the multi-ratiotransmission system further includes a shift-guiding component insertedand connected to the central axle. A circular guiding groove is firmedcoaxially with the first axis on the shift-guiding component. The shiftcable connector has an outer axial pin which is slidably inserted intothe circular guiding groove. The circular guiding groove extends for arange of angles in the circumferential direction. The range of angles iscorresponded to the range of predetermined angles of the rotation of thehollowed tube of the setting element controller.

According to an embodiment of the present invention, an insertion holeis formed at the center of the shift-guiding component. The two sides ofthe insertion hole are formed as two flat walls for abutting against theflat surfaces of the central axle, thereby preventing relative rotationbetween the central axle and the shift-guiding component.

According to an embodiment of the present invention, the one-way clutchincludes a clutch casing and at least one pin set. The clutch casing isintegrally formed with the annular gear. The clutch casing has anannular protrusion fir installing the sprocket, and at least onepin-fitting hole is formed on the annular protrusion. The at least onepin set is fitted inside the pin-fitting hole. The pin set includes apin, which is constantly pushed outward by a spring to engage with oneof the engaging holes formed on the sprocket, and is retracted from theengaging hole by an external force.

According to an embodiment of the present invention, the engaging holesof the sprocket are distributed along a circle, which is coaxial to saidfirst axis, with equal angular intervals in between every two adjacentengaging holes. Each engaging hole has a flat surface and an obliquesurface opposite to the flat surface. The flat surface is abuttedagainst the pin to transmit force in a given rotation direction. Theoblique surface serves as a cam and guides the pin outside the engaginghole upon contact to avoid force transmission in a rotation directionopposite to the given rotation direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be apparent to those skilled in the art byreading the following detailed description of a preferred embodimentthereof, with reference to the attached drawings, in which:

FIG. 1 is a schematic view illustrating a conventional derailleur systemof a bicycle;

FIG. 2 is a schematic view illustrating a conventional gear shiftingsystem of an automobile;

FIG. 3 is a schematic view illustrating a conventional planet gearsystem;

FIG. 4 is a perspective view of the first embodiment of a multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 5A is an exploded view of the first embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 5B is another exploded view of the first embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention;

FIG. 5C is a perspective sectional view of the first embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing is apart from the system;

FIG. 6A is perspective view of the first embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention, where the cylindrical casing and theannular bases of each planet gear sub-system are omitted for a betterview of the internal structure;

FIG. 6B is a side view of FIG. 6A;

FIG. 7 is a perspective view of the second embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 8A is an exploded view of the second embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 8B is another exploded view of the second embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention;

FIG. 8C is a perspective section view of the second embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing is apart from the system;

FIG. 9A is a perspective view of the second embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing and the annular bases of each planet gear sub-systems are omittedfor a better view of the internal structure;

FIG. 9B is a side view of FIG. 9A;

FIG. 9C is a sectional view of the second embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention, where some components are omitted;

FIG. 10 is a perspective view of the third embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 11A is an exploded view of the third embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 11B is another exploded view of the third embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention;

FIG. 11C is a perspective sectional view of the third embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing is apart from the system;

FIG. 12A is a perspective view of the third embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing and the annular bases of each planet gear sub-systems are omittedfor a better view of the internal structure;

FIG. 12B is a side view of FIG. 12A;

FIG. 13 is a perspective view of the fourth embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention;

FIG. 14A is an exploded view of the fourth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 14B is another exploded view of the fourth embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention;

FIG. 14C is a perspective view of the fourth embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing is apart from the system;

FIG. 15A is a perspective view of the fourth embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing and the annular bases of each planet gear sub-systems are omittedfor a better view of the internal structure;

FIG. 15B is a side view of FIG. 15A;

FIG. 16 is a perspective view of the fifth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 17A is an exploded view of the fifth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 17B is another exploded view of the fifth embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention;

FIG. 17C is a perspective sectional view of the fifth embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing is apart from the system;

FIG. 18A is a side view of the fifth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention, where the cylindrical casing isomitted for a better view of the internal structure;

FIG. 18B is a side view of the fifth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention, where the cylindrical casing isomitted for a better view of the internal structure;

FIG. 19 is a perspective view of the sixth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 20A is an exploded view of the sixth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention;

FIG. 20B is another exploded view of the sixth embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention;

FIG. 20C is a perspective sectional view of the sixth embodiment of themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to the present invention, where the cylindricalcasing is apart from the system;

FIG. 21A is a side view of the sixth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention, where the cylindrical casing isomitted for a better view of the internal structure; and

FIG. 21B is a side view of the sixth embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention, where the cylindrical casing isomitted for a better view of the internal structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention. The preferred embodiments are forillustrative purpose but to limit the scope of the present invention.Those who skilled in the art can make modification to the presentinvention within the scope defined by the claims of the presentinvention.

A multi-ratio transmission system with parallel vertical and coaxialplanet gears provided in the present invention mainly includes multipleplanet gear sub-systems. The planet gear sub-systems are coaxiallyplaced in series along a first axis, which is defined by the common axisof the planet gear sub-systems. Each planet gear sub-system includes acenter sun gear and at least one planet gear. The sun gear is disposedcoaxially with the first axis, and is able to optionally rotate aroundthe first axis. The planet gear is disposed coaxially with a secondaxis, which is perpendicular to the first axis, and is able to rotatearound the second axis. The second axis of the planet gear of eachplanet gear sub-system is configured to be perpendicular to the firstaxis, and is configured to be parallel with each other to form themulti-ratio transmission system with parallel vertical and coaxialplanet gears of the present invention.

Two adjacent planet gear sub-systems are coupled together with acoupling assembly, in this way, the rotation of the planet gear of theformer planet gear sub-system can be transmitted to the planet gear ofthe latter planet gear sub-system, thereby enabling the planet gears ofeach planet gear sub-system to rotate around the second axis.

Each planet gear sub-system further includes a setting element. Thesetting element can optionally move along the first axis so as tooptionally engage and secure the sun gear, or to disengage and releasethe sun gear. With the combination of the engaged sun gears and thedisengaged sun gears of the planet gear sub-systems, the presentinvention is able to provide different gear ratios.

The multi-ratio transmission system with parallel vertical and coaxialplanet gears of the present invention further includes a setting elementcontroller. The setting element controller is connected to the settingelement of each planet gear sub-system for optionally moving the settingelements. In this way, the setting elements of the planet gearsub-systems can optionally engage or disengage with each sun gear.

The multi-ratio transmission system with parallel vertical and coaxialplanet gears of the present invention further includes an annular gear.The annular gear is engaged with the planet gear of the planet gearsub-system.

In the multi-ratio transmission system with parallel vertical andcoaxial planet gears of the present invention as described above, thefirst planet gear sub-system, i.e. the front planet gear sub-system, canbe configured to be the input end, and the annular gear can beconfigured to be the output end (or the other way around). The planetgear sub-systems are placed in series along the first axis to form ahybrid planet gear system. Such hybrid planet gear system is able totransmit rotation speed or torque from the input end to the output end,and is able to further provide different gear ratios between the inputend and the output end. Meanwhile, by controlling the engagement statusbetween the setting element and the sun gear in each planet gearsub-system through the setting element controller, the gear ratios canbe changed.

The multi-ratio transmission system with parallel vertical and coaxialplanet gears of the present invention is featured by placing the planetgear sub-systems in series along a common axis, i.e. the first axis, andconfiguring the planet gear of each planet gear sub-system to beparallel to one another while being perpendicular to the common axis. Acoupling assembly is used to couple the planet gears of two adjacentplanet gear sub-systems. In this way, the overall size of themulti-ratio transmission system with parallel vertical and coaxialplanet gears can be greatly reduced, while multiple planet gearsub-systems can be placed in series and coupled together to form ahybrid planet gear system.

In the first embodiment of the present invention, the multi-ratiotransmission system of the present invention is placed in a bicyclewheel hub. Herein, the annular gear is configured to be the output endand is installed onto the spokes of the wheels. The first planet gearsub-system is configured to be the input end and is engaged with aninput gear, where the input gear is installed onto the sprockets of thebicycle. In this way, when the user rides on the bicycle, the torque istransmitted from the pedals through the sprockets to the first planetgear sub-system, and then the torque is passed through each planet gearsub-system to the annular gear. The annular gear then rotates the wheelvia the spokes of the wheels.

The user can move the setting elements in each planet gear sub-system tooptionally engage with the sun gear via the setting element controller,thereby changing the gear ratio of the transmission system.

First Embodiment

In the following section, the first embodiment of the multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to the present invention will be described with reference toFIG. 4, FIG. 5A, FIG. 5B, FIG. 5C, FIG. 6A and FIG. 6B.

In the figures of the present invention, the multi-ratio transmissionsystem with parallel vertical and coaxial planet gears is given the itemnumber 100. According to the first embodiment of the present invention,the multi-ratio transmission system 100 includes multiple planet gearsubsystems 102. In the first embodiment, the multi-ratio transmissionsystem 100 includes six planet gear sub-systems 102. The six planet gearsub-systems 102 are coaxially placed in series along a common axis,which is defined as a first axis 104. Each planet gear sub-system 102includes a sun gear 106, which is configured to rotate around the firstaxis 104. The sun gear 106 includes an outer gear 108 and an inner gear110. The outer gear 108 and the inner gear 110 are connected coaxiallyrelative to each other. The outer gear 108 is a bevel gear and islocated at an outer side of the inner gear 110.

Each planet gear sub-system 102 further includes at least one planetgear set 112 having a planet gear 114. The planet gear 114 is a bevelgear, and is able to engage with the outer gear 108 of the sun gear 106.The planet gear 114 is mounted on an axle 115 so as to rotate around asecond axis 116. The second axis 116 is perpendicular to the first axis104, and is defined by the axis of the axle 115. Notably, the secondaxis 116 of the planet gear 114 in each planet gear sub-system 102 isperpendicular to the first axis 104, and is configured to be parallelwith each other.

Considering the balance of the forces, each planet gear sub-system 102includes two planet gears 114 in the first embodiment. The two planetgears 114 are configured to be opposite to each other, in other words,the two planet gears 114 are 180 degrees apart from each other. However,the number of the planet gears 114 is not limited by the firstembodiment. If necessary, each planet gear sub-system 102 can includethree or more planet gears 114 that are configured symmetrically aboutthe axis (or not symmetrically about the axis).

A coupling assembly 118 is used to couple two adjacent planet gearsub-systems 102 together, so that rotation of the planet gear 114 of theformer planet gear sub-system 102 is transmitted to the planet gear 114of the latter planet gear sub-system 102. In the first embodiment, thecoupling assembly includes two pulleys 120. Each pulley 120 is connectedto the axles 115 of the planet gear sets 112 of the two adjacent planetgear sub-systems, so as to rotate in synchronization with the planetgears 114 of the planet gear sets 112. A belt 122 is trained around thetwo pulleys 120 to connect the two pulleys, so the rotation of theplanet gear 114 of the former planet gear sub-system is transmittedthrough the axle 115 and the pulleys 120 to the planet gear 114 of thelatter planet gear sub-system 102.

It is worth noting that except for the first (the front) and the last(the rear) planet gear sub-system 102, each axle 115 of the planet gear114 in the rest of the planet gear sub-systems is installed with twopulleys 120. The two pulleys 120 installed on the axle 115 are connectedto the pulley 120 of the former planet gear sub-systems 102 and to thepulley 120 of the latter planet gear sub-systems 102 via two belts 122.

Except for the combination of pulleys 120 and belts 122, those whoskilled in the art can use other means to set up the coupling assembly118. For example, one can replace the combination of pulleys 120 andbelts 122 with gear sets, which can also transmit the rotation of theplanet gear 114 of the former planet gear sub-system 102 to the planetgear 114 of the latter planet gear sub-system 102. Of course, there aremany other conventional methods to transmit the rotation motion betweentwo objects. If the conventional methods or mechanism used to transmitthe rotation motion are in the same field as the present invention, theyare considered to have the same effect with the mechanism used in thepresent invention, and therefore are within the protection scope of thepresent invention.

Another fact worth mentioning is that in the coupling assembly 118composed of the pulleys 120 and the belts 122, the belt 122 is made frommaterial with flexibility or elasticity. Although the belt 122 istensely stretched between two pulleys 120, it is still able to providefurther stretching in some degrees, which can provide the buffer effectwhile transmitting forces. In other words, the flexibility of the belt122 enables the same to serve as the “buffer”, which prevents the directand immediate transmission of the force. In this way, the forcetransmission between the pulleys 120 is smoother. In the human-powereddevices, for example the transmission system of the bicycle, suchcharacteristic is very useful. With the buffer effect provided duringthe transmission, the user would not feel the jumps, which is caused bythe difference in the acceleration, when shifting between different gearratios. In short, with the coupling assembly 118 composed of the beltsand pulleys, a smoother transmission can be obtained, thereby avoidingthe jumps, which is caused by the difference in the acceleration, whenshifting between gear ratios.

Furthermore, each planet gear sub-system 102 further includes a settingelement 124. The setting element is able to optionally move along thefirst axis 104, so as to engage and secure the sun gear 106 of theplanet gear sub-system 102, or to disengage and release the sun gear 106of the planet gear sub-system 102. In the first embodiment, the settingelement 124 is a crown gear and has a hollowed cylinder 126. The settingelement 124 is disposed coaxially with the sun gear 106, and is able tomove along the first axis 104 corresponding to the sun gear 106. Teeth128 are formed at an end of the hollowed cylinder 126 of the settingelement 124 facing the inner gear 110 of the sun gear 106. When thesetting element 124 moves toward the sun gear 106, the teeth 128 arethen engaged with the inner gear 110 of the sun gear 106, therebysecuring the sun gear 106. When the setting element 124 moves away fromthe sun gear 106, the teeth 128 of the setting element 124 aredisengaged from the inner gear 110, thereby releasing the sun gear 106for free rotation. With the configuration described above, differentgear ratios are provided based on the engagement statuses of the sungears 106 of the planet gear sub-systems 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a setting element controller 130. The setting elementcontroller 130 is connected to the setting element 124 of each planetgear sub-system 102, so as to enable the setting element 124 to engagethe sun gear 106 or disengage from the sun gear 106. In the firstembodiment, the setting element controller 130 includes a hollowed tube132. The hollowed tube 132 is disposed coaxially with the first axis104, and is able to rotate around the first axis 104 in a range ofpredetermined angles. The hollowed tube 132 has two ends. At least oneend of the hollowed tube 132 is installed with a rotation controller 133for optionally rotating the hollowed tube 132 within the range ofpredetermined angles. The hollowed tube 132 has an outer circumferentialsurface 134, where multiple cam grooves 136 are formed generally in thecircumferential direction. In the first embodiment, six cam grooves 136are formed corresponding to the setting elements 124 of the six planetgear sub-systems 102. The hollowed cylinder 126 of each setting element124 has an inner circumferential surface (not numbered). A control pin138 is installed on the inner circumferential surface in such way thatthe free end of the control pin 138 is inserted into the correspondingcam groove 136, so that the control pin 138 can move along the camgroove on the outer circumferential surface 134 in the circumferentialdirection. Hence, when the rotation controller 133 rotates the hollowedtube 132 of the setting element controller 130 in the range ofpredetermined angles, the setting elements 124 of all six planet gearsub-systems 102 move in the axial direction along the first axis 104corresponding to the cam grooves 136 due to the control pins 138inserted in the cam grooves 136. In this way, the setting elements 124moved closer to or away from the sun gears 106, and thereby engaging ordisengaging from the corresponding sun gears 106. By designing differentshapes for the cam grooves 136, each setting element 124 can move indifferent axial directions and thereby granting different gear ratios.

In the first embodiment, the depth of the cam groove 136 of the settingelement controller 130 is the same as the wall thickness of the hollowedtube 132; however, the depth of the cam groove 136 can also beconfigured to be smaller than the wall thickness of the hollowed tube132.

Each planet gear sub-system 102 further includes an annular base 140. Acircular wall structure is formed on the annular base 140 surroundingthe setting element 124 and the planet gears 114, and is coaxiallydisposed with the first axis 104. A hole 142 is drilled on the annularbase 140 corresponding to the axle 115 of the planet gear set 112 forfitting the axle 115. In the first embodiment, the inner end of the axle115 (located inside the annular base 140) and the outer end (locatedoutside the annular base 140) are installed with the planet gear 114 andthe pulley 120 respectively. In this way, the planet gear 114 is locatedinside the annular base 140, and the pulley 120 is located outside theannular base 140. However, in the first embodiment, the annular base 140of the first (the front) planet gear sub-system 102 is different fromthe annular base 140 of the last (the rear) planet gear sub-system 102.The details regarding this manner will be described later.

In the first embodiment, the annular bases 140 of the six planet gearsub-systems 102 of the multi-ratio transmission system 100 areinterconnected with each other, therefore relative rotation and relativeaxial movements are not allowed. Each annular base 140 has two axialends. The axial ends of the annular bases 140 abut against each other,so each annular base 140 cannot move in the axial direction of the firstaxis 104 separately. On the other hand, at least one axial groove 146 isformed on the outer side surface 144 of each annular base 140. The axialgroove extends from an axial end to another axial end of the annularbase 140 along the first axis 104. In the first embodiment, the outerside surface 144 of each annular base 140 has six axial grooves 146. Inaddition, six securing rods 148 are disposed along the first axis 104 insuch way that a part of each securing rod 148 is tightly fitted insidethe corresponding axial groove 146 of the annular base 140. In this way,the securing rods 148 penetrates through the axial grooves 146 of eachannular base 140 along the first axis 104 so as to prevent relativerotation between the annular bases 140.

The multi-ratio transmission system 100 of the present invention furtherincludes at least one annular gear 150 for engaging the planet gear 114of one of the planet gear sub-systems 102. In the first embodiment, themulti-ratio transmission system 100 includes two annular gears 150. Eachannular gear engages with the planet gear 114 of the first and the lastplanet gear sub-systems 102 respectively. In the first embodiment, theannular gear 150 is a crown gear. Teeth 152 are formed at one axial endof the annular gear 150, and the outer circumferential surface of theannular gear 150 is installed at an inner circumferential surface of acylindrical casing 154. Any conventional methods can be used to installthe annular gear 150 onto the cylindrical casing 154. In the firstembodiment, an outer thread 156 is formed on the outer circumferentialsurface of the annular gear 150 for engaging an inner thread 158 formedon the inner circumferential surface of the cylindrical casing 154. Inthis way, the annular gear 150 is mounted securely onto the cylindricalcasing 154. In the first embodiment, two annular gear 150 engage theplanet gears 114 of the first and the last planet gear sub-systems 102,therefore, the inner thread 158 is formed at the two ends of the innercircumferential surface of the cylindrical casing 154 respectively forengaging the outer threads 156 of the two annular gear 150. Then, therest of the planet gear sub-systems 102 are enclosed within thecylindrical casing 154.

According to the present invention, the planet gear set 112 of the firstand the last planet gear sub-system 102 further includes a transmissiongear 160. The transmission gear 160 is installed onto each axle 115 ofthe planet gear set 112, so that the transmission gear 160 is disposedcoaxially with the axles 115 of the planet gears 114 (coaxial with theaxis of the axle 115) and rotates in synchronization with the axles 115.Under this condition, the transmission gear 160 is engaged with theteeth 152 of the annular gear 150 to form the engagement relationshipbetween the annular gear 150 and the planet gear sub-system 102.

Hence, in correspondence to the configuration of the transmission gear160, the annular base of the first and the last planet gear sub-systems102 are different from the annular base 140 of the rest of the planetgear sub-systems 102 in the first embodiment. For clarity, the annularbases of the first and the last planet gear sub-system 102 in the firstembodiment are referred to as the “end annular base” in the followingsection, and is numbered as 140′. The rest of the annular bases 140 arerelated to as the “midsection annular base”. The end annular base 140′is formed with an inner circular wall 162 and an outer circular wall164. The inner circular wall 162 is formed with an axial end and isformed corresponding to the circular wall structure of the midsectionannular bases 140. The axial end of the end annular base 140′ is abuttedagainst the axial ends of the adjacent midsection annular base 140 asdescribed above. The outer circular wall 164 coaxially surrounds theinner circular wall 162, and is connected to the inner circular wall 162through a connecting portion 166 respectively at both ends. Similar tothe midsection annular bases 140, a hole 142 is formed at each innercircular wall 162 of the end annular base 140′ for fitting the axle 115of the planet gear 114. Similarly, another hole 168 is also formed onthe outer circular wall 164 for further fitting the axle 115. Thetransmission gear 160 connected to the axle 115 is located outside theouter circular wall 164 for engaging with the teeth 152 of the annulargear 150. In the first embodiment, two grooves 170 are formed at theconnecting portion 166 of the end annular base 140′ which is facing themidsection annular base 140. The two grooves 170 are the passage way forthe belt 122 of the coupling assembly 118 of the planet gear sub-system102, so the belt 122 passes through the two grooves 170 and are placedaround the pulleys 120 of the adjacent planet gear sub-system 102. Inaddition, six securing holes 172 are formed on the connecting portion166 for receiving and securing the end of the securing rods 148. In thisway, the two end annular bases 140′ are connected with the fourmidsection annular bases 140 to prevent relative movements or rotations.

The multi-ratio transmission system 100 of the present invention furtherincludes a central axle 174. The central axle 174 is disposed coaxiallywith the first axis 104, and is inserted to a center through hole 176 ofthe hollowed tube 132 of the setting element controller 130 by relativerotation. The central axle 174 enables the hollowed tube 132 to rotatearound the central axle 174, so when the rotation controller 133 rotatesthe hollowed tube 132 of the setting element controller 130 around thecentral axle 174, the setting element 124 moves in the axial directionon the outer circumferential surface 134 of the hollowed tube 132.

When in use, the two ends of the central axle 174 are secured onto theexternal securing portion respectively, so the rotation of the centralaxle 174 relative to the external securing portion is prevented. In thefirst embodiment, a flat surface 178 is formed at least one end of thecentral axle 174 for engaging with the external flat surface, therebypreventing rotation of the central axle 174.

According to the above configuration, the first (the front) planet gearsub-system 102 and the annular gear 150 of the multi-ratio transmissionsystem 100 of the present invention can be configured to be the inputend and the output end (or the other way around). The mid planet gearsub-systems 102 are placed in series along the first axis 104 to form ahybrid planet gear system for transmitting the torque or rotationbetween the input end and the output end, thereby providing differentgear ratios between the input end and the output end. Meanwhile, thesetting element controller 130 is available for controlling theengagement status of the setting element 124 of each planet gearsub-system 102, thereby changing the gear ratios.

Second Embodiment

In the following section, the multi-ratio transmission system withparallel vertical and coaxial planet gears 100 of the present inventionwill be explained as a transmission system of the bicycle.

The multi-ratio transmission system 100 according to a second embodimentof the present invention will be further explained with reference toFIG. 7, FIG. 8A, FIG. 8B, FIG. 5C, FIG. 9A and FIG. 9B.

The multi-ratio transmission system 100 of the present inventionincludes multiple planet gear sub-systems. In the second embodiment, themulti-ratio transmission system 100 includes six planet gear sub-systems102. The six planet gear sub-systems 102 are coaxially placed in seriesalong a common axis, which is defined as a first axis 104. Each planetgear sub-system 102 includes a sun gear 106, which is configured torotate around the first axis 104. The sun gear 106 includes an outergear 108 and an inner gear 110, and the outer gear 108 and the innergear 110 are connected coaxially relative to each other. The outer gear108 is a bevel gear and is located at an outer side of the inner gear110.

Each planet gear sub-system 102 further includes at least one planetgear set 112 having a planet gear 114. The planet gear 114 is a bevelgear, and is able to engage with the outer gear 108 of the sun gear 106.The planet gear 114 is disposed on an axle 115 so as to rotate around asecond axis 116. The second axis 116 is perpendicular to the first axis104, and is defined by the axis of the axle 115. Notably, the secondaxis 116 of the planet gear 114 in each planet gear sub-system 102 isperpendicular to the first axis 104, and is configured to be parallelwith each other.

Considering the balance of the forces, each planet gear sub-system 102includes two planet gears 114 in the second embodiment. The two planetgears 114 are configured to be opposite to each other, in other words,the two planet gears 114 are 180 degrees apart from each other. However,the number of the planet gears 114 is not limited by the secondembodiment. If necessary, each planet gear sub-system 102 can includethree or more planet gears 114 that are configured symmetrically aboutthe axis (or not symmetrically about the axis).

A coupling assembly 118 is used to couple two adjacent planet gearsub-systems 102 together, so that the rotation of the planet gear 114 ofthe former planet gear sub-system 102 is transmitted to the planet gear114 of the latter planet gear sub-system 102. In the second embodiment,the coupling assembly 118 includes two pulleys 120. Each pulley 120 isconnected to the axles 115 of the planet gear sets 112 of the twoadjacent planet gear sub-systems 102 so as to rotate in synchronizationwith the planet gears 114 of the planet gear sets 112. A belt 122 istrained around the two pulleys 120 to connect the two pulleys, so therotation of the planet gear 114 of the former planet gear sub-system istransmitted through the axle 115 and the pulleys 120 to the planet gear114 of the latter planet gear sub-system 102.

It is worth noting that except for the first (the front) and the last(the rear) planet gear sub-system 102, each axle 115 of the planet gear114 in the rest of the planet gear sub-systems is installed with twopulleys 120. The two pulleys 120 installed on the axle 115 are connectedto the pulley 120 of the former planet gear sub-systems 102 and to thepulley 120 of the latter planet gear sub-systems 102 with two belts 122.In the following description, the first planet gear planet sub-system102 is referred to the first planet gear sub-system 102 connectedadjacently to a sprocket 214 (please refer to the followingdescription). The last planet gear subsystem 102 is referred to the verylast planet gear sub-system 102 in the series of planet gear sub-systems102 relative to the first planet gear sub-system 102.

In addition, each planet gear sub-system 102 further includes a settingelement 124. The setting element 124 is able to optionally move alongthe first axis 104 so as to engage and secure the sun gear 106 of theplanet gear sub-system 102, or disengage from the sun gear 106 of theplanet gear sub-system 102. In the second embodiment, the settingelement 124 is a crown gear and has a hollowed cylinder 126. The settingelement 124 is disposed coaxially with the sun gear 106, and is able tomove along the first axis 104 corresponding to the sun gear 106. Teeth128 are formed at an end of the hollowed cylinder 126 of the settingelement 124 facing the inner gear 110 of the sun gear 106. When thesetting element 124 moves toward the sun gear 106, the teeth 128 engagethe inner gear 110 of the sun gear 106, thereby securing the sun gear106. When the setting element 124 moves away from the sun gear 106, theteeth 128 of the setting element 124 disengaged from the inner gear 110,thereby releasing the sun gear 106 for free rotation. With theconfiguration described above, different gear ratios are provided basedon the engagement statuses of the sun gears 106 of the planet gearsub-systems 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a setting element controller 130. The setting elementcontroller 130 is connected to the setting element 124 of each planetgear sub-system 102, so as to enable the setting element 124 to engagewith the sun gear 106 or to disengage from the sun gear 106. In thesecond embodiment, the setting element controller 130 includes ahollowed tube 132. The hollowed tube 132 is disposed coaxially with thefirst axis 104, and is able to rotate around the first axis 104 in arange of predetermined angles. The hollowed tube 132 has two ends. Atleast one end of the hollowed tribe 132 is installed with a rotationcontroller 133 for optionally rotating the hollowed tube 132 within therange of predetermined angles. The hollowed tube 132 has an outercircumferential surface 134, where multiple cam grooves 136 are formedgenerally in the circumferential direction. In the second embodiment,six cam grooves 136 are formed corresponding to the setting elements 124of the six planet gear sub-systems 102. The hollowed cylinder 126 ofeach setting element 124 has an inner circumferential surface (notnumbered). A control pin 138 is installed on the inner circumferentialsurface in such way that the free end of the control pin 138 is insertedinto the corresponding cam groove 136, so the control pin 138 movesalong the cam groove 136 on the outer circumferential surface 134 in thecircumferential direction. Hence, when the rotation controller 133rotates the hollowed tube 132 of the setting element controller 130 inthe range of predetermined angles, the setting elements 124 of all sixplanet gear sub-systems 102 move in the axial direction along the firstaxis 104 corresponding to the cam grooves 136 due to the control pins138 inserted in the cam grooves 136. In this way, the setting elements124 move closer to or away from the sun gears 106, and thereby engagingwith or disengaging from the corresponding sun gears 106. By designingdifferent shapes for different cam grooves 136, each setting element 124can move in different axial directions and thereby granting differentgear ratios.

In the second embodiment, the depth of the cam groove 136 of the settingelement controller 130 is the same as the wall thickness of the hollowedtube 132; however, the depth of the cam groove 136 can also beconfigured to be smaller than the wall thickness of the hollowed tube132.

Each planet gear sub-system 102 further includes an annular base 140. Acircular wall structure is formed on the annular base 140 surroundingthe setting element 124 and the planet gears 114, and is coaxiallydisposed with the first axis 104. A hole 142 is drilled on the annularbase 140 corresponding to the axle 115 of the planet gear set 112 forfitting the axle 115. In the second embodiment, the inner end of theaxle 115 (located inside the annular base 140) and the outer end(located outside the annular base 140) are installed with the planetgear 114 and the pulley 120 respectively. In this way, the planet gear114 is located inside the annular base 140, and the pulley 120 islocated outside the annular base 140.

In the second embodiment, the annular bases 140 of the first (the front)and the last (the rear) planet gear sub-systems 102 are different fromthe annular bases of the rest of the planet gear sub-systems 102. Forclarity, the annular bases of the first and the last planet gearsub-system 102 in the second embodiment are referred to as the “endannular base” in the following section, and is numbered as 140′. Therest of the annular bases 140 are referred to as the “midsection annularbase”. The end annular base 140′ is formed with an inner circular wall162 and an outer circular watt 164. The inner circular wall 162 isformed with an axial end and is formed corresponding to the circularwatt structure of the midsection annular bases 140. The outer circularwall 164 coaxially surrounds the inner circular wall 162, and isconnected to the inner circular wall 162 through a connecting portion166 respectively at both ends. Similar to the midsection annular bases140, a hole 142 is formed at each inner circular wall 162 of the endannular base 140′ for fitting the axle 115 of the planet gear 114.Similarly, another hole 168 is also formed on the outer circular wall164 for further fitting the axle 115. The transmission gear 160connected to the axle 115 is located outside the outer circular wall 164for engaging with the teeth 152 of the annular gear 150 (details ofwhich will be further described later).

In the second embodiment, the annular bases 140 of the six planet gearsub-systems 102 of the multi-ratio transmission system 100 areinterconnected with one another, therefore relative rotation andrelative axial movements are not allowed. Each midsection annular base140 has two axial ends. The axial ends of the midsection annular bases140 abut against one another, and an axial end of each end annular base140′ abuts against the axial end of the adjacent midsection annular base140, so each annular base 140 cannot move in the axial direction of thefirst axis 104 separately. On the other hand, at least one axial groove146 is formed on the outer side surface 144 of each midsection annularbase 140. The axial groove extends from an axial end to another axialend of the annular base 140 along the first axis 104. In the secondembodiment, the outer side surface 144 of each midsection annular base140 has six axial grooves 146. In addition, six securing rods 148 aredisposed along the first axis 104 in such way that a part of eachsecuring rod 148 is tightly fitted inside the corresponding axial groove146 of the midsection annular base 140. In this way, the securing rods148 penetrates through the axial grooves 146 of each midsection annularbase 140 along the first axis 104, so as to prevent relative rotationbetween the midsection annular bases 140.

In the second embodiment, two grooves 170 are formed at the connectingportion 166 of the end annular base 140′ facing the midsection annularbase 140. The two grooves 170 are the passage way for the belt 122 ofthe coupling assembly 118 of the planet gear sub-system 102, so the belt122 passes through the two grooves 170 so as to be trained around thepulleys 120 of the adjacent planet gear sub-system 102. In addition, sixsecuring holes 172 are formed on the connecting portion 166 forreceiving and securing the end of the securing rods 148. In this way,the two end annular bases 140′ are connected to the four midsectionannular bases 140 to prevent relative movements or rotations.

The multi-ratio transmission system 100 of the present invention furtherincludes at least one annular gear 150 for engaging with the planet gear114 of one of the planet gear sub-systems 102. In the second embodiment,the multi-ratio transmission system 100 includes two annular gears 150,each annular gear is engaged with the planet gear 114 the first and thelast planet gear sub-systems respectively. In the second embodiment, theannular gear 150 is a crown gear. Teeth 152 are formed at one axial endof the annular gear 150 for engaging with the corresponding planet gears114, and the outer circumferential surface of the annular gear 150corresponding to the first planet gear sub-system 102 is installed at aninner circumferential surface of a cylindrical casing 154. Anyconventional methods can be used to install the annular gear 150 ontothe cylindrical casing 154. In the second embodiment, an outer thread156 is formed on the outer circumferential surface of the annular gear150 for engaging with an inner thread 158 formed on the innercircumferential surface of the cylindrical casing 154. In this way, theannular gear 150 is mounted securely onto the cylindrical casing 154. Inthe second embodiment, two annular gears 150 engage with the planetgears 114 of the first and the last planet gear sub-systems 102,therefore, the inner thread 158 is formed at the two ends of the innercircumferential surface of the cylindrical casing 154 respectively forengaging with the outer threads 156 of the two annular gears 150. Then,the rest of the planet gear sub-systems 102 are enclosed within thecylindrical casing 154.

According to the present invention, the planet gear set 112 of the firstand the last planet gear sub-system 102 further includes a transmissiongear 160. The transmission gear 160 is installed onto each axle 115 ofthe planet gear set 112, so that the transmission gear 160 is disposedcoaxially with the axles 115 of the planet gears 114 (coaxial with theaxis of the axle 115) and rotates in synchronization with the axles 115.The transmission gear 160 is engaged with the teeth 152 of the annulargear 150 to form the engagement relationship between the annular gear150 and the planet gear sub-system 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a central axle 174. The central axle 174 is disposed coaxiallywith the first axis 104, and is inserted to a center through hole 176 ofthe hollowed tube 132 of the setting element controller 130 by relativerotation. The central axle 174 enables the hollowed tube 132 to rotatearound the central axle 174, so when the rotation controller 133 rotatesthe hollowed tube 132 of the setting element controller 130 around thecentral axle 174, the setting element 124 moves in the axial directionon the outer circumferential surface 134 of the hollowed tube 132.

In the second embodiment, the two ends of the central axle 174 aresecured to the bicycle rack respectively, so the central axle 174 ismounted to the bicycle rack and is prevented from relative motion orrotation. In the second embodiment, two flat surfaces 178 are formedopposite to each other at each end of the central axle 174. The flatsurfaces 178 can engage with the external flat surfaces to prevent therotation of the central axle 174. In addition, the flat surfaces 178also provide the space for other components to mount onto the centralaxle 174.

In the second embodiment, the multi-ratio transmission system furtherincludes a one-way clutch 200. The one-way clutch 200 is installed ontothe cylindrical casing 154 and is located outside of the first planetgear sub-system 102. The one-way clutch 200 includes a clutch casing 202and multiple pin sets 204. The clutch casing 202 is roughly acylindrical component having an inner axial end (not numbered) and anouter axial end (not numbered). The inner axial end is inserted into thecylindrical casing 154, and the outer axial end is located outside thecylindrical casing 154. The cylindrical component of the clutch casing202 has a side circumferential surface (not numbered). The outerdiameter of the side circumferential surface is roughly equal to theinner diameter of the cylindrical casing 154, so that the clutch casing202 can be inserted into the cylindrical casing 154. In addition, anouter thread 206 is formed on the side circumferential surface forengaging with the inner thread formed on the inner circumferentialsurface of the cylindrical casing 154. In this way, the one-way clutch200 can be installed inside the cylindrical casing 154. The inner threadformed on the inner circumferential surface of the cylindrical casing154 for securing the clutch casing 202 can be formed together with theinner thread 158 for securing the annular gear 150, as shown in thefigures illustrating the second embodiment. Alternatively, the two innerthreads can also be formed separately.

A through hole 208 is formed in the center of the clutch casing 202, andis configured to be coaxial with the first axis 104. The rotationcontroller 133 of the setting element controller 130 is rotatably fittedand supported in the through hole 208. The cross-section shape of thethrough hole 208 is formed corresponding to the rotation controller 133and the shape of the hollowed tube 132 installed on the rotationcontroller 133. This belongs to the common means of those who skilled inthe art, therefore it is not described in detail herein. A fact worthmentioning is that, a bearing 210 or other components with similarfunctions is disposed between the rotation controller 133 and thethrough hole 208 for steadily and rotatably supporting the rotationcontroller 133 of the setting element controller 130 and the hollowedtube 132.

An annular protrusion 212 is formed on the outer axial end of the clutchcasing 202, and is formed coaxially with and surrounding the throughhole 208 for coaxially supporting a sprocket 214. Multiple pin-fittingholes 216 are formed on the annular protrusion 212. In the secondembodiment, six pin-fitting holes 216 are formed on the annularprotrusions 212, but the number of the pin-fitting holes 216 can beadjusted according to different needs. Preferably, the pin-fitting holes216 are formed on the annular protrusion 212 in the circumferentialdirection with the same angular interval between every two adjacentpin-fitting holes 216. Each pin-fitting hole 216 is formed with a firstsection 218 and a second section 220, in which the first section 218 hasa larger diameter than the second section 220. A shoulder portion 222 isformed between the first section 218 and the second section 220. A pinset 204 is fitted inside each pin-fitting hole 216.

Each pin set 204 includes a housing 224 which is shaped as a hollowedcylinder and a pin 226 which is movably placed inside the housing 224. Aspring 228 is placed between the housing 224 and the pin 226 in such amanner that its inner end abuts against the shoulder portion 222 and itsouter end abuts against a flange of the pin 226. With the flexibility ofthe spring 228, the spring 228 pushes the outer end 230 of the pin 226outside the housing 224, and further engages the outer end 230 of thepin 226 with the engaging holes 232 formed on the sprocket 214. In thisway, the one-way clutch 200 engages the sprocket 214 to rotate togetherwith the sprocket 214.

With the flexibility of the spring 228, the pin 226 retracts back intothe casing 224 when the outer end 230 of the pin 226 is under internalstress. Under this condition, the inner end of the pin 226 is fittedinside the second section 220 of the pin-fitting hole 216 of the housing224, thereby avoiding interferences between the components.

Multiple engaging holes 232 are formed on the sprockets 214. Theengaging holes 232 are distributed along a circle, which is coaxial withthe first axis 104, with equal angular intervals between every twoadjacent engaging holes 232. Each engaging hole 232 has a front end anda back end (both not numbered) in the circumferential direction. Theback end has a flat surface, which abuts against the outer end 230 ofthe pin 226, fir transmitting the force. When the sprocket 214 rotatesforward, the back ends of the engaging holes 232 also rotate forwardwith the pins 226, thereby transmitting the torque and the rotationmotion to the multi-ratio transmission system 100 of the presentinvention. On the other hand, the front end of the engaging hole 232 isan oblique surface, which serves as a cam. The front end of the engaginghole 232 can guide the outer end 230 of the pin 226 to the outside ofthe engaging hole 232 when it comes into contact with the outer end 230of the pin 226. Hence, when the sprockets 214 rotates backward, the pin226 would not transmit the torque and the rotation motion to themulti-ratio transmission system 100 of the present invention due to theoblique surface of the front end of the engaging hole 232. In this way,the one-way clutch 200 is only able to transmit the torque and rotationmotion in one direction.

In the second embodiment, the multi-ratio transmission system 100 of thepresent invention further includes a shift cable connector 234. Theshift cable connector has an inner axial pin 236 for inserting into andconnecting with a connecting hole 238 of the rotation controller 133 ofthe setting element controller 130. The connecting hole 238 is formedeccentrically to the first axis 104, in this way, the shift cableconnector 234 can rotate the connecting hole 238 around the first axis104, and further drives the hollowed tube 132 of the rotation controller133 to rotate around the first axis 104, thereby shifting betweendifferent gear ratios.

A shift cable (not shown) can be installed onto the shift cableconnector 234. The shift cable can be the shift cable commonly seen onany bicycles, which is connected with a lever installed on the bicycle.When the user shifts the lever, the shift cable is then pulled by thelever and further rotates the setting element controller 130 through theshift cable connector 234.

In addition, an outer axial pin 240 is disposed on the shift cableconnector 234 opposite to the inner axial pin 236.

A shift-guiding component 242 is inserted and connected to the centralaxle 174. Especially, an insertion hole 244 is formed at the center ofthe shift-guiding component 242, in which the two sides of the insertionhole 244 are firmed as two flat walls 246 for abutting against the flatsurfaces 178 of the central axle 174, so as to prevent relative rotationbetween the two. In addition, a circular guiding groove 248 is formedcoaxially with the first axis 104 on the shift-guiding component 242.The circular guiding groove 248 extends in a range of angles along thecircumferential direction, in which the range of angles is correspondedto the range of predetermined angles for the rotation of the hollowedtube 132 of the setting element controller 130.

The outer axial pin 240 of the shift cable connector 234 is insertedinto the circular guiding groove 248 to move along the circular guidinggroove 248. When the user pulls the shift cable connector 234 throughthe shift cable, the outer axial pin 240 moves along the circularguiding groove 248, thereby achieving the shifting between differentgear ratios. Herein, a fact worth mentioning is that the two ends of thecircular guiding groove 248 serve as the stopper of the outer axial pin240 to prevent the outer axial pin 240 from moving out of range.

A restoring spring 250 is disposed between the shift-guiding component242 and the rotation controller 133 of the setting element controller130. The restoring spring 250 provides the restoring force of thesetting element controller 130 after the gear shifting, in which thesetting element controller 130 is pulled by the shift cable. In thesecond embodiment, the restoring spring 250 has two side ends 252, whichare inserted into the insertion hole 254 formed on the rotationcontroller 133 and the insertion hole 256 formed on the shift-guidingcomponent 242 respectively.

Third Embodiment

In the following paragraphs, the multi-ratio transmission system withparallel vertical and coaxial planet gears 100 of the present inventionwill be explained as a transmission system of the bicycle according to athird embodiment.

The multi-ratio transmission system 100 according to the thirdembodiment of the present invention will be further explained withreference to FIG. 10, FIG. 11A, FIG. 11B, FIG. 11C, FIG. 12A and FIG.12B.

The multi-ratio transmission system 100 of the present inventionincludes multiple planet gear sub-systems 102. In the third embodiment,the multi-ratio transmission system 100 includes six planet gearsub-systems 102. The six planet gear sub-systems 102 are coaxiallyplaced in series along a common axis, which is defined as a first axis104. Each planet gear sub-system 102 includes a sun gear 106, which isconfigured to rotate around the first axis 104. The sun gear 106includes an outer gear 108 and an inner gear 110, and the outer gear 108and the inner gear 110 are connected coaxially relative to each other.The outer gear 108 is a bevel gear and is located at an outer side ofthe inner gear 110.

Each planet gear sub-system 102 further includes at least one planetgear set 112 having a planet gear 114. The planet gear 114 is a bevelgear, and is able to engage with the outer gear 108 of the sun gear 106.The planet gear 114 is disposed on an axle 115 so as to rotate around asecond axis 116. The second axis 116 is perpendicular to the first axis104, and is defined by the axis of the axle 115. Notably, the secondaxis 116 of the planet gear 114 in each planet gear sub-system 102 isperpendicular to the first axis 104, and is configured to be parallelwith each other.

Considering the balance of the forces, each planet gear sub-system 102includes two planet gears 114 in the third embodiment. The two planetgears 114 are configured to be opposite to each other, in other words,the two planet gears 114 are 180 degrees apart from each other. However,the number of the planet gears 114 is not limited by the thirdembodiment. If necessary, each planet gear sub-system 102 includes threeor more planet gears 114 that are configured symmetrically about theaxis for not symmetrically about the axis).

A coupling assembly 118 is used to couple two adjacent planet gearsub-systems 102 together, so that the rotation of the planet gear 114 ofthe former planet gear sub-system 102 is transmitted to the planet gear114 of the latter planet gear sub-system 102. In the third embodiment,the coupling assembly 118 includes two pulleys 120. Each pulley 120 isconnected to the axles 115 of the planet gear sets 112 of the twoadjacent planet gear sub-systems 102 so as to rotate in synchronizationwith the planet gears 114 of the planet gear sets 112. A belt 122 istrained around the two pulleys 120 to connect the two pulleys, so thatthe rotation of the planet gear 114 of the former planet gear sub-systemis transmitted through the axle 115 and the pulleys 120 to the planetgear 114 of the latter planet gear sub-system 102.

It is worth noting that except for the first (the front) and the last(the rear) planet gear sub-system 102, each axle 115 of the planet gear114 in the rest of the planet gear sub-systems 102 is installed with twopulleys 120. The two pulleys 120 installed on the axle 115 are connectedto the pulley 120 of the former planet gear sub-systems 102 and to thepulley 120 of the latter planet gear sub-systems 102 via two belts 122.In the following description, the first planet gear planet sub-system102 is referred to the first planet gear sub-system 102 connectedadjacently to a sprocket 214 (please refer to the followingdescription). The last planet gear subsystem 102 is referred to the verylast planet gear sub-system 102 in the series of planet gear sub-systems102 relative to the first planet gear sub-system 102.

In addition, each planet gear sub-system 102 further includes a settingelement 124. The setting element 124 is able to optionally move alongthe first axis 104 so as to engage and secure the sun gear 106 of theplanet gear sub-system 102, or disengage from and release the sun gear106 of the planet gear sub-system 102. In the third embodiment, thesetting element 124 is a crown gear and has a hollowed cylinder 126. Thesetting element 124 is disposed coaxially with the sun gear 106, and isable to move along the first axis 104 corresponding to the sun gear 106.Teeth 128 are formed at an end of the hollowed cylinder 126 of thesetting element 124 facing the inner gear 110 of the sun gear 106. Whenthe setting element 124 moves toward the sun gear 106, the teeth 128engage with the inner gear 110 of the sun gear 106, thereby securing thesun gear 106. When the setting element 124 moves away from the sun gear106, the teeth 128 of the setting element 124 disengage from the innergear 110, thereby releasing the sun gear 106 for free rotation. With theconfiguration described above, different gear ratios are provided basedon the engagement statuses of the sun gears 106 of the planet gearsub-systems 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a setting element controller 130. The setting elementcontroller 130 is connected to the setting element 124 of each planetgear sub-system 102 so as to enable the setting element 124 to engagethe sun gear 106 or disengage from the sun gear 106. In the thirdembodiment, the setting element controller 130 includes a hollowed tube132. The hollowed tube 132 is disposed coaxially with the first axis104, and is able to rotate around the first axis 104 in a range ofpredetermined angles. The hollowed tube 132 has two ends. At least oneend of the hollowed tube 132 is installed with a rotation controller 133for optionally rotating the hollowed tube 132 within the range ofpredetermined angles. The hollowed tube 132 has an outer circumferentialsurface 134, where multiple cam grooves 136 are formed generally in thecircumferential direction. In the third embodiment, six cam grooves 136are formed corresponding to the setting elements 124 of the six planetgear sub-systems 102. The hollowed cylinder 126 of each setting element124 has an inner circumferential surface (not numbered). A control pin138 is installed on the inner circumferential surface in such way thatthe free end of the control pin 138 is inserted into the correspondingcam groove 136, so that the control pin 138 moves along the cam groove136 on the outer circumferential surface 134 in the circumferentialdirection. Hence, when the rotation controller 133 rotates the hollowedtube 132 of the setting element controller 130 in the range ofpredetermined angles, the setting elements 124 of all six planet gearsub-systems 102 move in the axial direction along the first axis 104corresponding to the cam grooves 136 due to the control pins 138inserted in the earn grooves 136. In this way, the setting elements 124are moved closer to or away from the sun gears 106, and thereby engagingwith or disengaging from the corresponding sun gears 106. By designingthe cam grooves 136 into different shapes, each setting element 124moves in different axial directions and thereby granting different gearratios.

In the third embodiment, the depth of the cam groove 136 of the settingelement controller 130 is the same as the wall thickness of the hollowedtube 132; however, the depth of the cam groove 136 can also beconfigured to be smaller than the wall thickness of the hollowed tube132.

Each planet gear sub-system 102 further includes an annular base 140. Acircular wall structure is formed on the annular base 140 surroundingthe setting element 124 and the planet gears 114, and is coaxiallydisposed with the first axis 104. A hole 142 is drilled on the annularbase 140 corresponding to the axle 115 of the planet gear set 112 forfitting the axle 115. In the third embodiment, the inner end of the axle115 (located inside the annular base 140) and the outer end (locatedoutside the annular base 140) are installed with the planet gear 114 andthe pulley 120 respectively. In this way, the planet gear 114 is locatedinside the annular base 140, and the pulley 120 is located outside theannular base 140.

In the third embodiment, the annular bases 140 of the first (the front)and the last (the rear) planet gear sub-systems 102 are different fromthe annular bases of the rest of the planet gear sub-systems 102. Forclarity, the annular bases of the first and the last planet gearsub-system 102 in the third embodiment are referred to as the “endannular base” in the following section, and is numbered as 140′. Therest of the annular bases 140 are referred to as the “midsection annularbase”. The end annular base 140′ is formed with an inner circular wall162 and an outer circular wall 164. The inner circular wall 162 isformed with an axial end and is formed corresponding to the circularwall structure of the midsection annular bases 140. The outer circularwall 164 coaxially surrounds the inner circular wall 162, and isconnected to the inner circular wall 162 through a connecting portion166 respectively at both ends. Similar to the midsection annular bases140, a hole 142 is formed at each inner circular wall 162 of the endannular base 140′ for fitting the axle 115 of the planet gear 114.Similarly, another hole 168 is also formed on the outer circular wall164 for further fitting the axle 115. The transmission gear 160connected to the axle 115 is located outside the outer circular wall 164for engaging with the teeth 152 of the annular gear 150 (The detailswill be further described later).

In the third embodiment, the annular bases 140 of the six planet gearsub-systems 102 of the multi-ratio transmission system 100 areinterconnected with each other, therefore relative rotation and relativeaxial movements are not allowed. Each midsection annular base 140 hastwo axial ends. The axial ends of the midsection annular bases 140 areabutted against each other, and an axial end of each end annular base140′ is abutted against the axial end of the adjacent midsection annularbase 140, so each annular base 140 cannot move in the axial direction ofthe first axis 104 separately. On the other hand, at least one axialgroove 146 is formed on the outer side surface 144 of each midsectionannular base 140. The at least one axial groove extends from an axialend to another axial end of the annular base 140 along the first axis104. In the third embodiment, the outer side surface 144 of eachmidsection annular base 140 has six axial grooves 146. In addition, sixsecuring rods 148 are disposed along the first axis 104 in such way thata part of each securing rod 148 is tightly fitted inside thecorresponding axial groove 146 of the midsection annular base 140. Inthis way; the securing rods 148 penetrates through the axial grooves 146of each midsection annular base 140 along the first axis 104 so as toprevent relative rotation between the midsection annular bases 140.

In the third embodiment, two grooves 170 are formed at the connectingportion 166 of the end annular base 140′ which is facing the midsectionannular base 140. The two grooves 170 are the passage way for the belt122 of the coupling assembly 118 of the planet gear sub-system 102, sothe belt 122 can be passed through the two grooves 170 to be placedaround the pulleys 120 of the adjacent planet gear sub-system 102. Inaddition, six securing holes 172 are formed on the connecting portion166 for receiving and securing the end of the securing rods 148. In thisway; the two end annular bases 140′ are connected with the fourmidsection annular bases 140 to prevent relative movements or rotations.

The multi-ratio transmission system 100 of the present invention furtherincludes at least one annular gear 150 for engaging with the planet gear114 of one of the planet gear sub-systems 102. In the third embodiment,the multi-ratio transmission system 100 includes two annular gears 150,each annular gear is engaged with the planet gear 114 the first and thelast planet gear sub-systems 102 respectively. In the third embodiment,the annular gear 150 is a crown gear. Teeth 152 are formed at one axialend of the annular gear 150 for engaging with the corresponding planetgears 114, and the outer circumferential surface of the annular gear 150corresponding to the first planet gear sub-system 102 is installed at aninner circumferential surface of a cylindrical casing 154. Anyconventional methods can be used to install the annular gear 150 ontothe cylindrical casing 154. In the third embodiment, an outer thread 156is formed on the outer circumferential surface of the annular gear 150for engaging with an inner thread 158 formed on the innercircumferential surface of the cylindrical casing 154. In this way, theannular gear 150 is mounted securely onto the cylindrical casing 154.The annular gear 150 corresponding to the first planet gear sub-system102 is installed onto a one-way clutch 200 (will be described later)with a shoulder portion 201 formed between the two. In the thirdembodiment, because the two annular gears 150 are engaged with theplanet gears 114 of the first and the last planet gear sub-systems 102respectively, the annular gear 150 corresponding to the last planet gearsub-system 102 is secured with the inner thread 158 at an end (rear end)of the cylindrical casing 154, and the annular gear 150 corresponding tothe first planet gear sub-system 102 is fitted at the other end (frontend) of the cylindrical casing 154. The rest of the planet gearsub-systems 102 are enclosed within the cylindrical casing 154.

In the third embodiment, except for the inner thread 158 formed at therear end of the cylindrical casing 154, an annular flange 300 is alsoformed inwardly at the front end of the cylindrical casing 154. Theannular flange 300 can be abutted against the annular gear 150 of theplanet gear sub-system 102 via a bearing 302 and the shoulder portion201 of the one-way clutch 200 to secure each planet gear sub-system 102inside the cylindrical casing 154.

In the third embodiment, the annular gear 150 installed at the front endof the cylindrical casing 154 is formed integrally with a clutch casing202 of the one-way clutch 200.

According to the present invention, the planet gear set 112 of the firstand the last planet gear sub-system 102 further includes a transmissiongear 160. The transmission gear 160 is installed onto each axle 115 ofthe planet gear set 112, so the transmission gear 160 is disposedcoaxially with the axles 115 of the planet gears 114 (coaxial with theaxis of the axle 115) and rotates in synchronization with the axles 115.The transmission gear 160 is engaged with the teeth 152 of the annulargear 150 to form the engagement relationship between the annular gear150 and the planet gear sub-system 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a central axle 174. The central axle 174 is disposed coaxiallywith the first axis 104, and is inserted to a center through hole 176 ofthe hollowed tube 132 of the setting element controller 130 by relativerotation. The central axle 174 enables the hollowed tube 132 to rotatearound the central axle 174, so when the rotation controller 133 rotatesthe hollowed tube 132 of the setting element controller 130 around thecentral axle 174, the setting element 124 is moved in the axialdirection on the outer circumferential surface 134 of the hollowed tube132.

In the third embodiment, the two ends of the central axle 174 aresecured to the bicycle rack respectively, so the central axle 174 ismounted to the bicycle rack and is prevented from relative motion orrotation. In the third embodiment, two flat surfaces 178 are formedopposite to each other at each end of the central axle 174. The flatsurfaces 178 can engage with the external flat surfaces to prevent therotation of the central axle 174. In addition, the flat surfaces 178 canalso provide the space for other components to mount onto the centralaxle 174.

In the third embodiment, the multi-ratio transmission system 100 of thepresent invention further includes the one-way clutch 200 locatedoutside of the first planet gear sub-system 102. The one-way clutch 200is abutted against the annular flange 300 of the cylindrical casing 154via the bearing 302 and the front annular gear 150. In the thirdembodiment, the one-way clutch 200 includes a clutch casing 202 andmultiple pin sets 204. The clutch casing 202 is roughly a cylindricalcomponent formed with an inner axial end (not numbered) and an outeraxial end (not numbered). The inner axial end of the clutch casing 202is installed onto the front annular gear 150 and is located inside thecylindrical casing 154 while the outer axial end of the clutch casing202 is located outside the cylindrical casing 154.

A through hole 208 is formed at the center of the clutch casing 202, andis configured to be coaxial with the first axis 104. The rotationcontroller 133 of the setting element controller 130 is rotatably fittedand supported in the through hole 208. The cross-section shape of thethrough hole 208 can be formed corresponding to the rotation controller133 and the shape of the hollowed tube 132 installed on the rotationcontroller 133. This belongs to the common means of those who skilled inthe art, therefore it is not described in detail herein. A fact worthmentioning is that a bearing 210 or other components with similarfunctions can be disposed between the rotation controller 133 and thethrough hole 208 for steadily and rotatably supporting the rotationcontroller 133 of the setting element controller 130 and the hollowedtube 132.

An annular protrusion 212 is formed on the outer axial end of the clutchcasing 202, and is formed coaxially with the through hole 208surrounding the through hole 208 for coaxially supporting a sprocket214. Multiple pin-fitting holes 216 are formed on the annular protrusion212. In the third embodiment, six pin-fitting holes 216 are formed onthe annular protrusions 212, but the number of the pin-fitting holes 216can be adjusted according to different needs. Preferably, thepin-fitting holes 216 are formed on the annular protrusion 212 in thecircumferential direction with the same angular interval in betweenevery two pin-fitting hole 216. Each pin-fitting hole 216 is formed witha first section 218 and a second section 220, in which the first section218 has a larger diameter than the second section 220. A shoulderportion 222 is formed between the first section 218 and the secondsection 220. A pin set 204 is fitted in each pin-fitting hole 216.

Each pin set 204 includes a housing 224 which is shaped as a hollowedcylinder and a pin 226 which is movably placed inside the housing 224. Aspring 228 is placed between the housing 224 and the pin 226 in such amanner that the inner end thereof is abutted against the shoulderportion 222 and the outer end thereof is abutted against a flange of thepin 226. With the flexibility of the spring 228, the spring 228 pushesthe outer end 230 of the pin 226 outside the housing 224, and furtherengages the outer end 230 of the pin 226 with the engaging holes 232formed on the sprocket 214. In this way, the one-way clutch 200 isengaged with the sprocket 214 to rotate with the sprocket 214.

With the flexibility of the spring 228, the pin 226 retracts back intothe casing 224 when the outer end 230 of the pin 226 is under internalstress. Under this condition, the inner end of the pin 226 can be fittedinside the second section 220 of the pin-fitting hole 216 of the housing224, thereby avoiding interferences between the components.

Multiple engaging holes 232 are formed on the sprockets 214. Theengaging holes 232 are distributed along a circle, which is coaxial withthe first axis 104, with equal angular intervals in between. Eachengaging hole 232 has a front end and a back end (both not numbered) inthe circumferential direction. The back end has a flat surface, whichcan be abutted against the outer end 230 of the pin 226, fortransmitting the force. When the sprocket 214 rotates forward, the backends of the engaging holes 232 also rotate forward with the pins 226,thereby transmitting the torque and the rotation motion to themulti-ratio transmission system 100 of the present invention. On theother hand, the front end of the engaging hole 232 is an obliquesurface, which can serve as a cam. The front end of the engaging hole232 can guide the outer end 230 of the pin 226 to the outside of theengaging hole 232 when it comes into contact with the outer end 230 ofthe pin 226. Hence, when the sprockets 214 rotates backward, the pin 226would not be able to transmit the torque and the rotation motion to themulti-ratio transmission system 100 of the present invention due to theoblique surface of the front end of the engaging hole 232. In this way,the one-way clutch 200 is only able to transmit the torque and rotationmotion in one direction.

In the third embodiment, the multi-ratio transmission system 100 of thepresent invention further includes a shift cable connector 234. Theshift cable connector has an inner axial pin 236 for inserting into andconnecting with a connecting hole 238 of the rotation controller 133 ofthe setting element controller 130. The connecting hole 238 is formedeccentrically to the first axis 104, in this way, the shift cableconnector 234 can rotate the connecting hole 238 to rotate around thefirst axis 104, and further drives the hollowed tube 132 of the rotationcontroller 133 to rotate around the first axis 104, thereby shiftingbetween different gear ratios.

A shift cable (not shown) can be installed onto the shift cableconnector 234. The shift cable can be the shift cable commonly seen onany bicycles, which is connected with a lever installed on the bicycle.When the user shifts the lever, the shift cable is then pulled by thelever and further rotates the setting element controller 130 through theshift cable connector 234.

In addition, an outer axial pin 240 is disposed on the shift cableconnector 234 opposite to the inner axial pin 236.

A shift-guiding component 242 is inserted and connected to the centralaxle 174. Especially, an insertion hole 244 is formed at the center ofthe shift-guiding component 242, in which the two sides of the insertionhole 244 are formed as two flat walls 246 for abutting against the flatsurfaces 178 of the central axle 174, so the relative rotation betweenthe two is prevented. In addition, a circular guiding groove 248 isformed coaxially with the first axis 104 on the shift-guiding component242. The circular guiding groove 248 extends in a range of angles alongthe circumferential direction, in which the range of angles correspondsto the range of predetermined angles for the rotation of the hollowedtube 132 of the setting element controller 130.

The outer axial pin 240 of the shift cable connector 234 is insertedinto the circular guiding groove 248 to move along the circular guidinggroove 248. When the user pulls the shift cable connector 234 throughthe shift cable, the outer axial pin 240 then moves along the circularguiding groove 248 and thereby achieving the shifting between differentgear ratios. Herein, a fact worth mentioning is that the two ends of thecircular guiding groove 248 can serve as the stopper of the outer axialpin 240 to prevent the outer axial pin 240 from moving out of range.

A restoring spring 250 is disposed between the shift-guiding component242 and the rotation controller 133 of the setting element controller130. The restoring spring 250 can server as the restoring force of thesetting element controller 130 after the gear shifting, in which thesetting element controller 130 is pulled by the shift cable. In thethird embodiment, the restoring spring 250 has two side ends 252, whichare inserted into the insertion hole 254 formed on the rotationcontroller 133 and the insertion hole 256 formed on the shift-guidingcomponent 242 respectively.

Fourth Embodiment

In the following section, the multi-ratio transmission system withparallel vertical and coaxial planet gears 100 of the present inventionwill be explained as a transmission system of the bicycle according to afourth embodiment.

The multi-ratio transmission system 100 according to the fourthembodiment of the present invention will be further explained withreference to FIG. 13, FIG. 14A, FIG. 14B, FIG. 14C, FIG. 15A and FIG.15B.

The multi-ratio transmission system 100 of the present inventionincludes multiple planet gear sub-systems 102. In the fourth embodiment,the multi-ratio transmission system 100 includes six planet gearsub-systems 102. The six planet gear sub-systems 102 are coaxiallyplaced in series along a common axis, which is defined as a first axis104. Each planet gear sub-system 102 includes a sun gear 106, which isconfigured to rotate around the first axis 104. The sun gear 106includes an outer gear 108 and an inner gear 110, and the outer gear 108and the inner gear 110 are connected coaxially relative to each other.The outer gear 108 is a bevel gear and is located at an outer side ofthe inner gear 110.

Each planet gear sub-system 102 further includes at least one planetgear set 112 having a planet gear 114. The planet gear 114 is a bevelgear, and is able to engage with the outer gear 108 of the sun gear 106.The planet gear 114 is disposed on an axle 115 so as to rotate around asecond axis 116. The second axis 116 is perpendicular to the first axis104, and is defined by the axis of the axle 115. Notably, the secondaxis 116 of the planet gear 114 in each planet gear sub-system 102 isperpendicular to the first axis 104, and is configured to be parallelwith each other.

Considering the balance of the forces, each planet gear sub-system 102includes two planet gears 114 in the fourth embodiment. The two planetgears 114 are configured to be opposite to each other, in other words,the two planet gears 114 are 180 degrees apart from each other. However,the number of the planet gears 114 is not limited by the fourthembodiment. If necessary, each planet gear sub-system 102 includes threeor more planet gears 114 that are configured symmetrically about theaxis for not symmetrically about the axis).

A coupling assembly 118 is used to couple two adjacent planet gearsub-systems 102 together, so that the rotation of the planet gear 114 ofthe former planet gear sub-system 102 is transmitted to the planet gear114 of the latter planet gear sub-system 102. In the fourth embodiment,the coupling assembly 118 includes two pulleys 120. Each pulley 120 isconnected to the axles 115 of the planet gear sets 112 of the twoadjacent planet gear sub-systems 102 so as to rotate in synchronizationwith the planet gears 114 of the planet gear sets 112. A belt 122 istrained around the two pulleys 120 to connect the two pulleys, so thatthe rotation of the planet gear 114 of the former planet gear sub-systemis transmitted through the axle 115 and the pulleys 120 to the planetgear 114 of the latter planet gear sub-system 102.

It is worth noting that except for the first (the front) and the last(the rear) planet gear sub-systems 102, each axle 115 of the planet gear114 in the rest of the planet gear sub-systems 102 is installed with twopulleys 120. The two pulleys 120 installed on the axle 115 are connectedto the pulley 120 of the former planet gear sub-systems 102 and to thepulley 120 of the latter planet gear sub-systems 102 via two belts 122.In the following description, the first planet gear planet sub-system102 is referred to the first planet gear sub-system 102 connectedadjacently to a sprocket 214 (please refer to the followingdescription). The last planet gear subsystem 102 is referred to the verylast planet gear sub-system 102 in the series of planet gear sub-systems102 relative to the first planet gear sub-system 102.

In addition, each planet gear sub-system 102 further includes a settingelement 124. The setting element 124 is able to optionally move alongthe first axis 104 so as to engage and secure the sun gear 106 of theplanet gear sub-system 102, or to disengage and release the sun gear 106of the planet gear sub-system 102. In the fourth embodiment, the settingelement 124 is a crown gear and has a hollowed cylinder 126. The settingelement 124 is disposed coaxially with the sun gear 106, and is able tomove along the first axis 104 corresponding to the sun gear 106. Teeth128 are formed at an end of the hollowed cylinder 126 of the settingelement 124 facing the inner gear 110 of the sun gear 106. When thesetting element 124 moves toward the sun gear 106, the teeth 128 engagethe inner gear 110 of the sun gear 106, thereby securing the sun gear106. When the setting element 124 moves away from the sun gear 106, theteeth 128 of the setting element 124 disengage from the inner gear 110,thereby releasing the sun gear 106 for free rotation. With theconfiguration described above, different gear ratios are provided basedon the engagement statuses of the sun gears 106 of the planet gearsub-systems 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a setting element controller 130. The setting elementcontroller 130 is connected to the setting element 124 of each planetgear sub-system 102 so as to enable the setting element 124 to engagewith the sun gear 106 or to disengage from the sun gear 106. In thefourth embodiment, the setting element controller 130 includes ahollowed tube 132. The hollowed tube 132 is disposed coaxially with thefirst axis 104, and is able to rotate around the first axis 104 in arange of predetermined angles. The hollowed tube 132 has two ends. Atleast one end of the hollowed tube 132 is installed with a rotationcontroller 133 for optionally rotating the hollowed tube 132 within therange of predetermined angles. The hollowed tube 132 has an outercircumferential surface 134, where multiple cam grooves 136 are formedgenerally in the circumferential direction. In the fourth embodiment,six cam grooves 136 are formed corresponding to the setting elements 124of the six planet gear sub-systems 102. The hollowed cylinder 126 ofeach setting element 124 has an inner circumferential surface (notnumbered). A control pin 138 is installed on the inner circumferentialsurface in such way that the free end of the control pin 138 is insertedinto the corresponding cam groove 136, so that the control pin 138 canmove along the cam groove 136 on the outer circumferential surface 134in the circumferential direction. Hence, when the rotation controller133 rotates the hollowed tube 132 of the setting element controller 130in the range of predetermined angles, the setting elements 124 of allsix planet gear sub-systems 102 move in the axial direction along thefirst axis 104 corresponding to the cam grooves 136 due to the controlpins 138 inserted in the cam grooves 136. In this way, the settingelements 124 are moved closer to or away from the sun gears 106, therebyengaging with or disengaging from the corresponding sun gears 106. Bydesigning the cam grooves 136 into different shapes, each settingelement 124 can move in different axial directions, thereby grantingdifferent gear ratios.

In the fourth embodiment, the depth of the cam groove 136 of the settingelement controller 130 is the same as the wall thickness of the hollowedtube 132; however, the depth of the cam groove 136 can also beconfigured to be smaller than the wall thickness of the hollowed tube132.

Each planet gear sub-system 102 further includes an annular base 140. Acircular wall structure is formed on the annular base 140 surroundingthe setting element 124 and the planet gears 114, and is coaxiallydisposed with the first axis 104. A hole 142 is drilled on the annularbase 140 corresponding to the axle 115 of the planet gear set 112 forfitting the axle 115. In the fourth embodiment, the inner end of theaxle 115 (located inside the annular base 140) and the outer end(located outside the annular base 140) are installed with the planetgear 114 and the pulley 120 respectively. In this way, the planet gear114 is located inside the annular base 140, and the pulley 120 islocated outside the annular base 140.

In the fourth embodiment, the annular bases 140 of the first and thelast planet gear sub-systems 102 are different from the annular bases ofthe rest of the planet gear sub-systems 102. For clarity, the annularbases of the first and the last planet gear sub-system 102 in the fourthembodiment are related to as the “end annular base” in the followingparagraphs, and is numbered as 140′. The rest of the annular bases 140are referred to as the “midsection annular base”.

In the fourth embodiment, the annular bases 140 of the six planet gearsub-systems 102 of the multi-ratio transmission system 100 areinterconnected with one another, therefore relative rotation andrelative axial movements are not allowed. Each midsection annular base140 has two axial ends. The axial ends of the midsection annular bases140 abut against one another, and an axial end of each end annular base140′ abuts against the axial end of the adjacent midsection annular base140, so that each annular base 140 cannot move in the axial direction ofthe first axis 104 separately. On the other hand, at least one axialgroove 146 is formed on the outer side surface 144 of each midsectionannular base 140. The axial groove extends from an axial end to anotheraxial end of the annular base 140 along the first axis 104. In thefourth embodiment, the outer side surface 144 of each midsection annularbase 140 has six axial grooves 146. In addition, six securing rods 148are disposed along the first axis 104 in such way that a part of eachsecuring rod 148 is tightly fitted inside the corresponding axial groove146 of the midsection annular base 140. In this way, the securing rods148 penetrates through the axial grooves 146 of each midsection annularbase 140 along the first axis 104 so as to prevent relative rotationbetween the midsection annular bases 140.

In the fourth embodiment, six securing holes 172 are formed on theconnecting portion 166 for receiving and securing the end of thesecuring rods 148. In this way, the two end annular bases 140′ areconnected with the four midsection annular bases 140 to prevent relativemovements or rotations.

The multi-ratio transmission system 100 of the present invention furtherincludes at least one annular gear 150 for engaging with the planet gear114 of one of the planet gear sub-systems 102. In the fourth embodiment,the multi-ratio transmission system 100 includes only one annular gear150, which is engaged with the planet gear 114 of the first planet gearsub-system 102. In the fourth embodiment, the annular gear 150 is acrown gear. Teeth 152 are formed at one axial end of the annular gear150 for engaging with corresponding planet gears 114. A outercircumferential surface of the annular gear 150 is installed at an innercircumferential surface of a cylindrical casing 154. Any conventionalmethods can be used to install the annular gear 150 onto the cylindricalcasing 154. In the fourth embodiment, an outer thread 156 is formed onthe outer circumferential surface of the annular gear 150 for engagingwith an inner thread 158 formed on the inner circumferential surface ofthe cylindrical casing 154. In this way, the annular gear 150 is securedonto the cylindrical casing 154. In the fourth embodiment, because theannular gear 150 is engaged with the planet gear set 112 of the firstplanet gear sub-system 102, the inner thread 158 is formed on the innercircumferential surface at the end (front end) of the cylindrical casing154, which is corresponded to the first planet gear sub-system 102, forengaging with the outer thread 156 of the annular gear 150.

In the fourth embodiment, an annular flange 400 is formed inwardly atthe rear end of the cylindrical casing, which is corresponded to thelast planet gear sub-system 102 and is opposite from the front end ofthe cylindrical casing 154. The annular flange 400 can be abuttedagainst the axial end (not numbered) of the annular base 140 of the lastplanet gear sub-system 102 through a bearing 402. The abutted axial endof the annular base is opposite from the mid planet gear sub-system 102.In this way, with the engagement between the annular gear 150 and theinner thread 158 of the cylindrical casing 154, each planet gearsub-systems can be secured inside the cylindrical casing 154.

According to the present invention, the planet gear set 112 of the firstplanet gear sub-system 102 further includes a transmission gear 160. Thetransmission gear 160 is installed onto each axle 115 of the planet gearset 112, so the transmission gear 160 is disposed coaxially with theaxles 115 of the planet gears 114 (coaxial with the axis of the axle115) and rotates in synchronization with the axles 115. The transmissiongear 160 is engaged with the teeth 152 of the annular gear 150 to formthe engagement relationship between the annular gear 150 and the planetgear sub-system 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a central axle 174. The central axle 174 is disposed coaxiallywith the first axis 104, and is inserted to a center through hole 176 ofthe hollowed tube 132 of the setting element controller 130 by relativerotation. The central axle 174 enables the hollowed tube 132 to rotatearound the central axle 174, so when the rotation controller 133 rotatesthe hollowed tube 132 of the setting element controller 130 around thecentral axle 174, the setting element 124 is moved in the axialdirection on the outer circumferential surface 134 of the hollowed tube132.

In the fourth embodiment, the two ends of the central axle 174 aresecured to the bicycle rack respectively, so the central axle 174 ismounted to the bicycle rack and is prevented from relative motion orrotation. In the fourth embodiment, two flat surfaces 178 are formedopposite to each other at each end of the central axle 174. The flatsurfaces 178 can engage with the external flat surfaces to prevent therotation of the central axle 174. In addition, the flat surfaces 178 canalso provide the space for other components to mount onto the centralaxle 174.

In the fourth embodiment, the multi-ratio transmission system 100 of thepresent invention further includes a one-way clutch 200 disposed outsideof the first planet gear sub-system 102. In the fourth embodiment, theone-way clutch 200 includes a clutch casing 202 and multiple pin sets204. Herein, the annular gear 150 is integrally formed with the clutchcasing 202 of the one-way clutch 200, so the one-way clutch 200 can beinstalled onto the cylindrical casing 154 by the outer thread 156 of theannular gear 150 and the inner thread 158 of the cylindrical casing 154.The clutch casing 202 is roughly a cylindrical component formed with aninner axial end (not numbered) and an outer axial end (not numbered).The inner axial end is integrally formed with the annular gear 150 andis fitted inside the cylindrical casing 154 for the outer thread 156 ofthe annular gear 150 to engage with the inner thread 158 of thecylindrical casing 154. The outer axial end is located outside of thecylindrical casing 154.

A through hole 208 is formed at the center of the clutch casing 202, andis configured to be coaxial with the first axis 104. The rotationcontroller 133 of the setting element controller 130 is rotatably fittedand supported in the through hole 208. The cross-section shape of thethrough hole 208 can be formed corresponding to the rotation controller133 and the shape of the hollowed tube 132 installed on the rotationcontroller 133. This belongs to the common means of those who skilled inthe art, therefore it is not described in detail herein. A fact worthmentioning is that a bearing 210 or other components with similarfunctions can be disposed between the rotation controller 133 and thethrough hole 208 for steadily and rotatably supporting the rotationcontroller 133 of the setting element controller 130 and the hollowedtube 132.

An annular protrusion 212 is formed on the outer axial end of the clutchcasing 202, and is formed coaxially with the through hole 208surrounding the through hole 208 for coaxially supporting a sprocket214. Multiple pin-fitting holes 216 are formed on the annular protrusion212. In the fourth embodiment, six pin-fitting holes 216 are formed onthe annular protrusions 212, but the number of the pin-fitting holes 216can be adjusted according to different needs. Preferably, thepin-fitting holes 216 are formed on the annular protrusion 212 in thecircumferential direction with the same angular interval in betweenevery two adjacent pin-fitting hole 216. Each pin-fitting hole 216 isformed with a first section 218 and a second section 220, in which thefirst section 218 has a larger diameter than the second section 220. Ashoulder portion 222 is formed between the first section 218 and thesecond section 220. A pin set 204 is fitted in each pin-fitting hole216.

Each pin set 204 includes a housing 224 which is shaped as a hollowedcylinder and a pin 226 which is movably placed inside the housing 224. Aspring 228 is placed between the housing 224 and the pin 226 in suchmanner that its inner end abuts against the shoulder portion 222 and itsouter end abuts against a flange of the pin 226. With the flexibility ofthe spring 228, the spring 228 pushes the outer end 230 of the pin 226outside the housing 224, and further engages the outer end 230 of thepin 226 with the engaging holes 232 formed on the sprocket 214. In thisway, the one-way clutch 200 is engaged with the sprocket 214 to rotatewith the sprocket 214.

With the flexibility of the spring 228, the pin 226 retracts back intothe casing 224 when the outer end 230 of the pin 226 is under internalstress. Under this condition, the inner end of the pin 226 can be fittedinside the second section 220 of the pin-fitting hole 216 of the housing224, thereby avoiding interferences between the components.

Multiple engaging holes 232 are formed on the sprockets 214. Theengaging holes 232 are distributed along a circle, which is coaxial withthe first axis 104, with equal angular intervals in between. Eachengaging hole 232 has a front end and a back end (both not numbered) inthe circumferential direction. The back end has a flat surface, whichcan be abutted against the outer end 230 of the pin 226, fortransmitting the force. When the sprocket 214 rotates forward, the backends of the engaging holes 232 also rotate forward with the pins 226,thereby transmitting the torque and the rotation motion to themulti-ratio transmission system 100 of the present invention. On theother hand, the front end of the engaging hole 232 is an obliquesurface, which can serve as a cam. The front end of the engaging hole232 can guide the outer end 230 of the pin 226 to the outside of theengaging hole 232 when it comes into contact with the outer end 230 ofthe pin 226. Hence, when the sprockets 214 rotates backward, the pin 226would not be able to transmit the torque and the rotation motion to themulti-ratio transmission system 100 of the present invention due to theoblique surface of the front end of the engaging hole 232. In this way,the one-way clutch 200 is only able to transmit the torque and rotationmotion in one direction.

In the fourth embodiment, the multi-ratio transmission system 100 of thepresent invention further includes a shift cable connector 234. Theshift cable connector has an inner axial pin 236 for inserting into andconnecting with a connecting hole 238 of the rotation controller 133 ofthe setting element controller 130. The connecting hole 238 is formedeccentrically to the first axis 104, in this way, the shift cableconnector 234 can rotate the connecting hole 238 to rotate around thefirst axis 104, and further drives the hollowed tube 132 of the rotationcontroller 133 to rotate around the first axis 104, thereby shiftingbetween different gear ratios.

A shift cable (not shown) can be installed onto the shift cableconnector 234. The shift cable can be the shift cable commonly seen onany bicycles, which is connected with a lever installed on the bicycle.When the user shifts the lever, the shift cable is then pulled by thelever and further rotates the setting element controller 130 through theshift cable connector 234.

In addition, an outer axial pin 240 is disposed on the shift cableconnector 234 opposite to the inner axial pin 236.

A shift-guiding component 242 is inserted and connected to the centralaxle 174. Especially, an insertion hole 244 is formed at the center ofthe shift-guiding component 242, in which the two sides of the insertionhole 244 are formed as two flat walls 246 for abutting against the flatsurfaces 178 of the central axle 174, so the relative rotation betweenthe two is prevented. In addition, a circular guiding groove 248 isformed coaxially with the first axis 104 on the shift-guiding component242. The circular guiding groove 248 extends in a range of angles alongthe circumferential direction, in which the range of angles correspondsto the range of predetermined angles for the rotation of the hollowedtube 132 of the setting element controller 130.

The outer axial pin 240 of the shift cable connector 234 is insertedinto the circular guiding groove 248 to move along the circular guidinggroove 248. When the user pulls the shift cable connector 234 throughthe shift cable, the outer axial pin 240 then moves along the circularguiding groove 248 and thereby achieving the shifting between differentgear ratios. Herein, a fact worth mentioning is that the two ends of thecircular guiding groove 248 can serve as the stopper of the outer axialpin 240 to prevent the outer axial pin 240 from moving out of range.

A restoring spring 250 is disposed between the shift-guiding component242 and the rotation controller 133 of the setting element controller130. The restoring spring 250 can server as the restoring force of thesetting element controller 130 after the gear shifting, in which thesetting element controller 130 is pulled by the shift cable. In thefourth embodiment, the restoring spring 250 has two side ends 252, whichare inserted into the insertion hole 254 formed on the rotationcontroller 133 and the insertion hole 256 formed on the shift-guidingcomponent 242 respectively.

Fifth Embodiment

In the following section, the multi-ratio transmission system withparallel vertical and coaxial planet gears 100 of the present inventionwill be explained as a transmission system of the bicycle according to afifth embodiment.

The multi-ratio transmission system 100 according to the fifthembodiment of the present invention will be further explained withreference to FIG. 16, FIG. 17A, FIG. 117B, FIG. 17C, FIG. 18A and FIG.189.

The multi-ratio transmission system 100 of the present inventionincludes multiple planet gear sub-systems 102. In the fifth embodiment,the multi-ratio transmission system 100 includes six planet gearsub-systems 102. The six planet gear sub-systems 102 are coaxiallyplaced in series along a common axis, which is defined as a first axis104. Each planet gear sub-system 102 includes a sun gear 106, which isconfigured to rotate around the first axis 104. The sun gear 106includes an outer gear 108 and an inner gear 110, and the outer gear 108and the inner gear 110 are connected coaxially relative to each other.The outer gear 108 is a bevel gear and is located at an outer side ofthe inner gear 110.

Each planet gear sub-system 102 further includes at least one planetgear set 112 having a planet gear 114. The planet gear 114 is a bevelgear, and is able to engage with the outer gear 108 of the sun gear 106.The planet gear 114 is disposed on an axle 115 so as to rotate around asecond axis 116. The second axis 116 is perpendicular to the first axis104, and is defined by the axis of the axle 115. Notably, the secondaxis 116 of the planet gear 114 in each planet gear sub-system 102 isperpendicular to the first axis 104, and is configured to be parallelwith each other.

Considering the balance of the forces, each planet gear sub-system 102includes two planet gears 114 in the fifth embodiment. The two planetgears 114 are configured to be opposite to each other, in other words,the two planet gears 114 are 180 degrees apart from each other. However,the number of the planet gears 114 is not limited by the fifthembodiment. If necessary, each planet gear sub-system 102 can includethree or more planet gears 114 that are configured symmetrically aboutthe axis (or not symmetrically about the axis).

A coupling assembly 118 is used to couple two adjacent planet gearsub-systems 102 together, so the rotation of the planet gear 114 of theformer planet gear sub-system 102 is transmitted to the planet gear 114of the latter planet gear sub-system 102. In the fifth embodiment, thecoupling assembly 118 includes two small gears 500. Each small gear 500is connected to the axles 115 of the planet gear sets 112 of the twoadjacent planet gear sub-systems 102 so as to rotate in synchronizationwith the planet gears 114 of the planet gear sets 112. A coupling gearplate 502 is disposed between the two small gears 500 to connect the twosmall gears 500, so that the rotation of the planet gear 114 of theformer planet gear sub-system 102 is transmitted to the planet gear 114of the latter planet gear sub-system 102 through the axle 115, the twosmall gears 500 and the coupling gear plate 502.

In the fifth embodiment, the coupling gear plate 502 has a first axialend surface and a second axial end surface. A crown gear 504 is formedon the first and second axial end surfaces respectively for engagingwith the small gears 500 of the planet gear sets 112 of the two adjacentplanet gear sub-systems 102.

In the fifth embodiment, the two crown gears 504 on the two sides of thecoupling gear plate 502 are configured to have different diameters. Thesmall gears 500 to be engaged with the crown gears 504 are located at adifferent distance from the first axis 104 respectively. With differentdistance from the first axis 104, the rotation speed of the two smallgears 500 on the two sides of the coupling plate 502 are different fromeach other. In the fifth embodiment, the two adjacent coupling plates502 are symmetrically disposed with each other; in other words, thecrown gear 504 with the larger diameter of the former coupling gearplate 502 is symmetric with the crown gear 504 of with the largerdiameter of the latter coupling gear plate 502. For example, the twocrown gears 504 with larger diameters are disposed facing each other orare disposed facing away from each other. Similarly, the crown gears 504with smaller diameters of the two adjacent coupling gear plates 502 aresymmetrically disposed with each other, so every other small gear 500has the same rotation speed. Hence, every two adjacent planet gearsub-systems 102 can be seen as a group in the fifth embodiment, in whichthe two plane gears 114 rotate with different rotation speed. Sinceevery group of the planet gear sub-system 102 has the same operationcondition, the six planet gear sub-systems 102 of the fifth embodimentare divided into three groups of planet gear sub-systems 102 with thesame operation conditions.

It is worth noting that the small gears 500 of the first (the front) andthe last (the rear) planet gear sub-systems 102 are engaged with twoannular gears 150 respectively (please refer to the followingdescription). In the following description, the first planet gear planetsub-system 102 is referred to the first planet gear sub-system 102connected adjacently to a sprocket 214 (please refer to the followingdescription). The last planet gear subsystem 102 is referred to the verylast planet gear sub-system 102 in the series of planet gear sub-systems102 relative to the first planet gear sub-system 102.

In addition, each planet gear sub-system 102 further includes a settingelement 124. The setting element 124 is able to optionally move alongthe first axis 104 so as to engage and secure the sun gear 106 of theplanet gear sub-system 102, or to disengage from and release the sungear 106 of the planet gear sub-system 102. In the fifth embodiment, thesetting element 124 is a crown gear and has a hollowed cylinder 126. Thesetting element 124 is disposed coaxially with the sun gear 106, and isable to move along the first axis 104 corresponding to the sun gear 106.Teeth 128 are formed at an end of the hollowed cylinder 126 of thesetting element 124 facing the inner gear 110 of the sun gear 106. Whenthe setting element 124 moves toward the sun gear 106, the teeth 128engage with the inner gear 110 of the sun gear 106, thereby securing thesun gear 106. When the setting element 124 moves away from the sun gear106, the teeth 128 of the setting element 124 disengage from the innergear 110, thereby releasing the sun gear 106 for free rotation. With theconfiguration described above, different gear ratios are provided basedon the engagement statuses of the sun gears 106 of the planet gearsub-systems 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a setting element controller 130. The setting elementcontroller 130 is connected to the setting element 124 of each planetgear sub-system 102 so as to enable the setting element 124 to engagewith the sun gear 106 or disengage from the sun gear 106. In the fifthembodiment, the setting element controller 130 includes a hollowed tube132. The hollowed tube 132 is disposed coaxially with the first axis104, and is able to rotate around the first axis 104 in a range ofpredetermined angles. The hollowed tube 132 has two ends. At least oneend of the hollowed tube 132 is installed with a rotation controller 133for optionally rotating the hollowed tube 132 within the range ofpredetermined angles. The hollowed tube 132 has an outer circumferentialsurface 134, where multiple cam grooves 136 are formed generally in thecircumferential direction. In the fifth embodiment, six cam grooves 136are formed corresponding to the setting elements 124 of the six planetgear sub-systems 102. The hollowed cylinder 126 of each setting element124 has an inner circumferential surface (not numbered). A control pin138 is installed on the inner circumferential surface in such way thatthe free end of the control pin 138 is inserted into the correspondingcam groove 136, so that the control pin 138 moves along the cam groove136 on the outer circumferential surface 134 in the circumferentialdirection. Hence, when the rotation controller 133 rotates the hollowedtube 132 of the setting element controller 130 in the range ofpredetermined angles, the setting elements 124 of all six planet gearsub-systems 102 move in the axial direction along the first axis 104corresponding to the cam grooves 136 due to the control pins 138inserted in the cam grooves 136. In this way, the setting elements 124are moved closer to or away from the sun gears 106, thereby engagingwith or disengaging from the corresponding sun gears 106. By designingthe cam grooves 136 into different shapes, each setting element 124 canmove in different axial directions, thereby granting different gearratios.

In the fifth embodiment, the depth of the cam groove 136 of the settingelement controller 130 is the same as the wall thickness of the hollowedtube 132; however, the depth of the cam groove 136 can also beconfigured to be smaller than the wall thickness of the hollowed tube132.

Each planet gear sub-system 102 further includes an annular base 140. Acircular wall structure is formed on the annular base 140 surroundingthe setting element 124 and the planet gears 114, and is coaxiallydisposed with the first axis 104. A hole 142 is drilled on the annularbase 140 corresponding to the axle 115 of the planet gear set 112 forfitting the axle 115. In the fifth embodiment, the inner end of the axle115 (located inside the annular base 140) and the outer end (locatedoutside the annular base 140) are installed with the planet gear 114 andthe small gear 500 respectively. In this way, the planet gear 114 islocated inside the annular base 140, and the small gear 500 is locatedoutside the annular base 140.

As mentioned above, the two adjacent planet gear sub-systems 102 make agroup in the fifth embodiment; therefore, the annular bases 140 of thetwo adjacent planet gear sub-systems 102 are also formed integrally, asshown in the figures.

In addition, the multi-ratio transmission system 100 according to thefifth embodiment further includes a bearing 506. The bearing 506 isdisposed surrounding the crown gears 504 with smaller diameters of theadjacent two coupling gear plates 502 and the small gears 500 engagedtherewith, thereby supporting the coupling gear plate 502 to rotatesmoothly on the inner circumferential surface of the cylindrical casing154.

The multi-ratio transmission system 100 of the present invention furtherincludes at least one annular gear 150 for engaging with the small gears500 of one of the planet gear set 112 of one of the planet gearsub-systems 102. In the fifth embodiment, the multi-ratio transmissionsystem 100 includes two annular gears 150, each annular gear is engagedwith the small gear 500 the first and the last planet gear sub-systems102 respectively. In the fifth embodiment, the annular gear 150 is acrown gear. Teeth 152 are formed at one axial end of the annular gear150 for engaging with the corresponding planet gear 114. The annulargear corresponding to the last planet gear sub-system 102 is securedinside the cylindrical casing 154 with a circular securing end cap 508.The securing end cap 508 is formed with a center hole 510 for rotatablyfitting the annular gear 105 corresponding to the last planet gearsub-system 102. The securing end cap 508 has an outer circumferentialsurface for installing onto an inner circumferential surface of thecylindrical casing 154. Any conventional methods can be used to installthe securing end cap 508 onto the cylindrical casing 154. In the fifthembodiment, an outer thread 512 is formed on the outer circumferentialsurface of the securing end cap 508 for engaging with an inner thread158 formed on the inner circumferential surface of the cylindricalcasing 154. In this way, the securing end cap 508 is secured onto thecylindrical casing 154. The annular gear 150 corresponding to the firstplanet gear sub-system 102 is installed onto a one-way clutch 200(described in the later sections), and a shoulder portion 201 is formedbetween the two. In the fifth embodiment, because the two annular gears150 are engaged with the small gears 500 of the planet gear sets 112 ofthe first and the last planet gear sub-systems 102, therefore, inaddition to the annular gear 150 corresponding to the last planet gearsub-system 102 being secured to an end of the cylindrical casing 154(rear end), the annular gear 150 corresponding to the first planet gearsub-system 102 is fitted at the other end (front end) of the cylindricalcasing 154. The rest of the planet gear sub-systems 102 are enclosedwithin the cylindrical casing 154.

In the fifth embodiment, in addition to the inner thread 158 formed atthe rear end of the cylindrical casing 154, an annular flange 300 isalso formed inwardly at the front end of the cylindrical casing 154. Theannular flange 300 abuts against the annular gear 150 of the planet gearsub-system and the shoulder portion 201 of the one-way clutch 200 with abearing 302. In this way, each planet gear sub-systems is secured insidethe cylindrical casing 154 to ensure the engagement relationship betweeneach small gear 500 and each crown gear 504 of the coupling gear plate502.

In the fifth embodiment, the front annular gear 150 is integrally formedwith the clutch casing 202 of the one-way clutch 200.

The multi-ratio transmission system 100 of the present invention furtherincludes a central axle 174. The central axle 174 is disposed coaxiallywith the first axis 104, and is inserted to a center through hole 176 ofthe hollowed tube 132 of the setting element controller 130 by relativerotation. The central axle 174 enables the hollowed tube 132 to rotatearound the central axle 174, so when the rotation controller 133 rotatesthe hollowed tube 132 of the setting element controller 130 around thecentral axle 174, the setting element 124 moves in the axial directionon the outer circumferential surface 134 of the hollowed tube 132.

In the fifth embodiment, the two ends of the central axle 174 aresecured to the bicycle rack respectively, so that the central axle 174is mounted to the bicycle rack and is prevented from relative motion orrotation. In the fifth embodiment, two flat surfaces 178 are formedopposite to each other at each end of the central axle 174. The flatsurfaces 178 can engage with the external flat surfaces to prevent therotation of the central axle 174. In addition, the flat surfaces 178also provide the space for other components to mount onto the centralaxle 174.

In the fifth embodiment, the multi-ratio transmission system 100 of thepresent invention further includes a one-way clutch 200 disposed outsideof the first planet gear sub-system 102. The one-way clutch 200 abutsagainst the annular flange 300 of the cylindrical casing 154 with thebearing 302 and the front annular gear 150. In the fifth embodiment, theone-way clutch 200 includes a clutch casing 202 and multiple pin sets204. The clutch casing 202 is roughly a cylindrical component formedwith an inner axial end (not numbered) and an outer axial end (notnumbered). The inner axial end is installed onto the front annular gear150 and is located inside the cylindrical casing 154. The outer axialend is located outside of the cylindrical casing 154.

A through hole 208 is formed at the center of the clutch casing 202, andis configured to be coaxial with the first axis 104. The rotationcontroller 133 of the setting element controller 130 is rotatably fittedand supported in the through hole 208. The cross-section shape of thethrough hole 208 is formed corresponding to the rotation controller 133and the shape of the hollowed tube 132 installed on the rotationcontroller 133. This belongs to the common means of those who skilled inthe art, therefore it is not described in detail herein. A fact worthmentioning is that a bearing 210 or other components with similarfunctions are disposed between the rotation controller 133 and thethrough hole 208 for steadily and rotatably supporting the rotationcontroller 133 of the setting element controller 130 and the hollowedtube 132.

An annular protrusion 212 is formed on the outer axial end of the clutchcasing 202, and is formed coaxially with the through hole 208surrounding the through hole 208 for coaxially supporting a sprocket214. Multiple pin-fitting holes 216 are formed on the annular protrusion212. In the fifth embodiment, six pin-fitting holes 216 are formed onthe annular protrusions 212, but the number of the pin-fitting holes 216can be adjusted according to different needs. Preferably, thepin-fitting holes 216 are formed on the annular protrusion 212 in thecircumferential direction with the same angular interval between everytwo adjacent pin-fitting holes 216. Each pin-fitting hole 216 is formedwith a first section 218 and a second section 220, in which the firstsection 218 has a larger diameter than the second section 220. Ashoulder portion 222 is formed between the first section 218 and thesecond section 220. A pin set 204 is fitted in each pin-fitting hole216.

Each pin set 204 includes a housing 224 which is shaped as a hollowedcylinder and a pin 226 which is movably placed inside the housing 224. Aspring 228 is placed between the housing 224 and the pin 226 in such amanner that its inner end abuts against the shoulder portion 222 and itsouter end abuts against a flange of the pin 226. With the flexibility ofthe spring 228, the spring 228 pushes the outer end 230 of the pin 226outside the housing 224, and further engages the outer end 230 of thepin 226 with the engaging holes 232 formed on the sprocket 214. In thisway, the one-way clutch 200 is engaged with the sprocket 214 to rotatewith the sprocket 214.

With the flexibility of the spring 228, the pin 226 retracts back intothe casing 224 when the outer end 230 of the pin 226 is under internalstress. Under this condition, the inner end of the pin 226 is fittedinside the second section 220 of the pin-fitting hole 216 of the housing224, thereby avoiding interferences between the components.

Multiple engaging holes 232 are formed on the sprockets 214. Theengaging holes 232 are distributed along a circle, which is coaxial withthe first axis 104, with equal angular intervals therebetween. Eachengaging hole 232 has a front end and a back end (both not numbered) inthe circumferential direction. The back end has a flat surface, whichabuts against the outer end 230 of the pin 226, for transmitting theforce. When the sprocket 214 rotates forward, the back ends of theengaging holes 232 also rotate forward with the pins 226, therebytransmitting the torque and the rotation motion to the multi-ratiotransmission system 100 of the present invention. On the other hand, thefront end of the engaging hole 232 is an oblique surface, which servesas a cam. The front end of the engaging hole 232 can guide the outer end230 of the pin 226 to the outside of the engaging hole 232 when it comesinto contact with the outer end 230 of the pin 226. Hence, when thesprockets 214 rotates backward, the pin 226 would not transmit thetorque and the rotation motion to the multi-ratio transmission system100 of the present invention due to the oblique surface of the front endof the engaging hole 232. In this way, the one-way clutch 200 is onlyable to transmit torque and rotation motion in one direction.

In the fifth embodiment, the multi-ratio transmission system 100 of thepresent invention further includes a shift cable connector 234. Theshift cable connector has an inner axial pin 236 for inserting into andconnecting with a connecting hole 238 of the rotation controller 133 ofthe setting element controller 130. The connecting hole 238 is formedeccentrically to the first axis 104, in this way, the shift cableconnector 234 can rotate the connecting hole 238 to rotate around thefirst axis 104, and further drives the hollowed tube 132 of the rotationcontroller 133 to rotate around the first axis 104, thereby shiftingbetween different gear ratios.

A shift cable (not shown) is installed onto the shift cable connector234. The shift cable can be the shift cable commonly seen on anybicycles, which is connected with a lever installed on the bicycle. Whenthe user shifts the lever, the shift cable is then pulled by the leverand further rotates the setting element controller 130 through the shiftcable connector 234.

In addition, an outer axial pin 240 is disposed on the shift cableconnector 234 opposite to the inner axial pin 236.

A shift-guiding component 242 is inserted and connected to the centralaxle 174. Especially, an insertion hole 244 is formed at the center ofthe shift-guiding component 242, in which the two sides of the insertionhole 244 are formed as two flat walls 246 for abutting against the flatsurfaces 178 of the central axle 174, so that relative rotation betweenthe two is prevented. In addition, a circular guiding groove 248 isformed coaxially with the first axis 104 on the shift-guiding component242. The circular guiding groove 248 extends in a range of angles alongthe circumferential direction, in which the range of angles iscorresponded to the range of predetermined angles for the rotation ofthe hollowed tithe 132 of the setting element controller 130.

The outer axial pin 240 of the shift cable connector 234 is insertedinto the circular guiding groove 248 to move along the circular guidinggroove 248. When the user pulls the shift cable connector 234 throughthe shift cable, the outer axial pin 240 then moves along the circularguiding groove 248, thereby achieving the shifting between differentgear ratios. Herein, a fact worth mentioning is that the two ends of thecircular guiding groove 248 serve as the stopper of the outer axial pin240 to prevent the outer axial pin 240 from moving out of range.

A restoring spring 250 is disposed between the shift-guiding component242 and the rotation controller 133 of the setting element controller130. The restoring spring 250 serves as the restoring force of thesetting element controller 130 after the gear shifting, in which thesetting element controller 130 is pulled by the shift cable. In thefifth embodiment, the restoring spring 250 has two side ends 252, whichare inserted into the insertion hole 254 formed on the rotationcontroller 133 and the insertion hole 256 formed on the shift-guidingcomponent 242 respectively.

Sixth Embodiment

In the following paragraphs, the multi-ratio transmission system withparallel vertical and coaxial planet gears 100 of the present inventionwill be explained as a transmission system of the bicycle according to asixth embodiment.

The multi-ratio transmission system 100 according to the sixthembodiment of the present invention will be further explained withreference to FIG. 19, FIG. 20A, FIG. 20B, FIG. 20C, FIG. 21A and FIG.21B.

The multi-ratio transmission system 100 of the present inventionincludes multiple planet gear sub-systems 102. In the sixth embodiment,the multi-ratio transmission system 100 includes six planet gearsub-systems 102. The six planet gear sub-systems 102 are coaxiallyplaced in series along a common axis, which is defined as a first axis104. Each planet gear sub-system 102 includes a sun gear 106, which isconfigured to rotate around the first axis 104. The sun gear 106includes an outer gear 108 and an inner gear 110, and the outer gear 108and the inner gear 110 are connected coaxially relative to each other.The outer gear 108 is a bevel gear and is located at an outer side ofthe inner gear 110.

Each planet gear sub-system 102 further includes at least one planetgear set 112 having a planet gear 114. The planet gear 114 is a bevelgear, and is able to engage with the outer gear 108 of the sun gear 106.The planet gear 114 is disposed on an axle 115 so as to rotate around asecond axis 116. The second axis 116 is perpendicular to the first axis104, and is defined by the axis of the axle 115. Notably, the secondaxis 116 of the planet gear 114 in each planet gear sub-system 102 isperpendicular to the first axis 104, and is configured to be parallelwith each other.

Considering the balance of the forces, each planet gear sub-system 102includes two planet gears 114 in the sixth embodiment. The two planetgears 114 are configured to be opposite to each other, in other words,the two planet gears 114 are 180 degrees apart from each other. However,the number of the planet gears 114 is not limited by the sixthembodiment. If necessary, each planet gear sub-system 102 includes threeor more planet gears 114 that are configured symmetrically about theaxis (or not symmetrically about the axis).

A coupling assembly 118 is used to couple two adjacent planet gearsub-systems 102 together, so that the rotation of the planet gear 114 ofthe former planet gear sub-system 102 is transmitted to the planet gear114 of the latter planet gear sub-system 102. In the sixth embodiment,the coupling assembly 118 includes two small gears 500. Each small gear500 is connected to the axles 115 of the planet gear sets 112 of the twoadjacent planet gear sub-systems 102 so as to rotate in synchronizationwith the planet gears 114 of the planet gear sets 112. A coupling gearplate 502 is disposed between the two small gears 500 to connect the twosmall gears 500, so that the rotation of the planet gear 114 of theformer planet gear sub-system 102 is transmitted to the planet gear 114of the latter planet gear sub-system 102 through the axle 115, the twosmall gears 500 and the coupling gear plate 502.

In the sixth embodiment, the coupling gear plate 502 has a first axialend surface and a second axial end surface. A crown gear 504 is formedon the first and second axial end surfaces respectively for engagingwith the small gears 500 of the planet gear sets 112 of the two adjacentplanet gear sub-systems 102.

In the sixth embodiment, the two crown gears 504 on the two sides ofsome of the coupling gear plates 502 are configured to have differentdiameters. The small gears 500 to engage with the crown gears 504 arelocated at a different distance from the first axis 104 respectively.With different distance from the first axis 104, the rotation speed ofthe two small gears 500 on the two sides of the coupling plates 502 aredifferent from each other. On the other hand, the two crown gears 504 onthe two sides of the other coupling gear plates 502 are configured tohave the same diameter. Hence, the rotation speed of the small gears 500of such coupling gear plates 502 are the same.

Herein, for clarity, the gear coupling plate 502 which has two crowngears 504 with different diameters is referred to as the first gearcoupling plate 502. The gear coupling plate 502 which has the two crowngears 504 with the same diameter is referred to as the second gearcoupling plate 502. In the sixth embodiment, the two first gear couplingplates 502 are disposed symmetrically with each other with a second gearcoupling plate 502 disposed therebetween. In other words, the crown gear504 with larger diameter of the former first gear coupling gear plate502 is disposed symmetrically with the crown gear 504 with largerdiameter of the latter first gear coupling gear plate 502. For example,the two crown gears 504 with larger diameters are disposed facing eachother or are disposed facing away from each other. Similarly, the twocrown gears 504 with smaller diameters of the first gear coupling gearplate 502 are also disposed symmetrically with each other. With theconfiguration that a second gear coupling plate 502 is sandwichedbetween two first gear coupling plates 502, every three adjacent planetgear sub-systems 102 can be seen as a group. In addition, the planetgear 114 of the first planet gear sub-systems 102 has a differentrotation speed from the two planet gears 114 of the last two planet gearsub-systems 102, but the two planet gears 114 of the last two planetgear sub-systems 102 have the same rotation speed.

It is worth noting that the small gears 500 of the first (the front) andthe last (the rear) planet gear sub-systems 102 are engaged with twoannular gears 150 respectively (please refer to the followingdescriptions). In the following description, the first planet gearplanet sub-system 102 is referred to the first planet gear sub-system102 connected adjacently to a sprocket 214 (please refer to thefollowing description). The last planet gear subsystem 102 is referredto the very last planet gear sub-system 102 in the series of planet gearsub-systems 102 relative to the first planet gear sub-system 102.

In addition, each planet gear sub-system 102 further includes a settingelement 124. The setting element 124 is able to optionally move alongthe first axis 104 so as to engage with and secure the sun gear 106 ofthe planet gear sub-system 102, or to disengage from and release the sungear 106 of the planet gear sub-system 102. In the fifth embodiment, thesetting element 124 is a crown gear and has a hollowed cylinder 126. Thesetting element 124 is disposed coaxially with the sun gear 106, and isable to move along the first axis 104 corresponding to the sun gear 106.Teeth 128 are formed at an end of the hollowed cylinder 126 of thesetting element 124 facing the inner gear 110 of the sun gear 106. Whenthe setting element 124 moves toward the sun gear 106, the teeth 128engage with the inner gear 110 of the sun gear 106, thereby securing thesun gear 106. When the setting element 124 moves away from the sun gear106, the teeth 128 of the setting element 124 disengage from the innergear 110, thereby releasing the sun gear 106 for free rotation. With theconfiguration described above, different gear ratios are provided basedon the engagement statuses of the sun gears 106 of the planet gearsub-systems 102.

The multi-ratio transmission system 100 of the present invention furtherincludes a setting element controller 130. The setting elementcontroller 130 is connected to the setting element 124 of each planetgear sub-system 102 so as to enable the setting element 124 to engagewith the sun gear 106 or disengage from the sun gear 106. In the sixthembodiment, the setting element controller 130 includes a hollowed tube132. The hollowed tube 132 is disposed coaxially with the first axis104, and is able to rotate around the first axis 104 in a range ofpredetermined angles. The hollowed tube 132 has two ends. At least oneend of the hollowed tube 132 is installed with a rotation controller 133for optionally rotating the hollowed tube 132 within the range ofpredetermined angles. The hollowed tube 132 has an outer circumferentialsurface 134, where multiple cam grooves 136 are formed generally in thecircumferential direction. In the sixth embodiment, six cam grooves 136are formed corresponding to the setting elements 124 of the six planetgear sub-systems 102. The hollowed cylinder 126 of each setting element124 has an inner circumferential surface (not numbered). A control pin138 is installed on the inner circumferential surface in such way thatthe free end of the control pin 138 is inserted into the correspondingcam groove 136, so that the control pin 138 moves along the cam groove136 on the outer circumferential surface 134 in the circumferentialdirection. Hence, when the rotation controller 133 rotates the hollowedtube 132 of the setting element controller 130 in the range ofpredetermined angles, the setting elements 124 of all six planet gearsub-systems 102 move in the axial direction along the first axis 104corresponding to the cam grooves 136 due to the control pins 138inserted in the cam grooves 136. In this way, the setting elements 124move closer to or away from the sun gears 106, thereby engaging with ordisengaging from the corresponding sun gears 106. By designing the camgrooves 136 into different shapes, each setting element 124 moves indifferent axial directions, thereby granting different gear ratios.

In the sixth embodiment, the depth of the cam groove 136 of the settingelement controller 130 is the same as the wall thickness of the hollowedtube 132; however, the depth of the cam groove 136 can also beconfigured to be smaller than the wall thickness of the hollowed tube132.

Each planet gear sub-system 102 further includes an annular base 140. Acircular wall structure is formed on the annular base 140 surroundingthe setting element 124 and the planet gears 114, and is coaxiallydisposed with the first axis 104. A hole 142 is drilled on the annularbase 140 corresponding to the axle 115 of the planet gear set 112 forfitting the axle 115. In the sixth embodiment, the inner end of the axle115 (located inside the annular base 140) and the outer end (locatedoutside the annular base 140) are installed with the planet gear 114 andthe small gear 500 respectively. In this way, the planet gear 114 islocated inside the annular base 140, and the small gear 500 is locatedoutside the annular base 140.

As mentioned above, the planet gear sub-systems 102 are grouped in thesixth embodiment; therefore, the annular bases 140 of the two adjacentplanet gear sub-systems 102 are integrally formed as shown in thefigures.

In addition, the multi-ratio transmission system 100 according to thesixth embodiment further includes a bearing 506. The bearing 506 isdisposed surrounding the crown gears 504 with smaller diameters of thecoupling gear plates 502 and the small gears 500 engaged therewith,thereby supporting the coupling gear plate 502 to rotate smoothly on theinner circumferential surface of the cylindrical casing 154.

The multi-ratio transmission system 100 of the present invention furtherincludes at least one annular gear 150 for engaging with the small gears500 of one of the planet gear set 112 of one of the planet gearsubsystems 102. In the sixth embodiment, the multi-ratio transmissionsystem 100 includes two annular gears 150, each annular gear is engagedwith the small gear 500 the first and the last planet gear sub-systems102 respectively. In the sixth embodiment, the annular gear 150 is acrown gear. Teeth 152 are formed at one axial end of the annular gear150 for engaging with the corresponding planet gear 114. The annulargear corresponding to the last planet gear sub-system 102 is securedinside the cylindrical casing 154 with a circular securing end cap 508.The securing end cap 508 is formed with a center hole 510 for rotatablyfitting the annular gear 105 corresponding to the last planet gearsub-system 102. The securing end cap 508 has an outer circumferentialsurface for installing onto an inner circumferential surface of thecylindrical casing 154. Any conventional methods can be used to installthe securing end cap 508 onto the cylindrical casing 154. In the sixthembodiment, an outer thread 512 is formed on the outer circumferentialsurface of the securing end cap 508 for engaging with an inner thread158 formed on the inner circumferential surface of the cylindricalcasing 154. In this way, the securing end cap 508 is secured onto thecylindrical casing 154. The annular gear 150 corresponding to the firstplanet gear sub-system 102 is installed onto a one-way clutch 200 (willbe described in later paragraphs), and a shoulder portion 201 is formedbetween the two. In the sixth embodiment, because the two annular gears150 are engaged with the small gears 500 of the planet gear sets 112 ofthe first and the last planet gear sub-systems 102, therefore, inaddition to the annular gear 150 corresponding to the last planet gearsub-system 102 being secured to an end of the cylindrical casing 154(rear end), the annular gear 150 corresponding to the first planet gearsub-system 102 is fitted at the other end (front end) of the cylindricalcasing 154. The rest of the planet gear sub-systems 102 are enclosedwithin the cylindrical casing 154.

In the sixth embodiment, in addition to the inner thread 158 formed atthe rear end of the cylindrical casing 154, an annular flange 300 isalso formed inwardly at the front end of the cylindrical casing 154. Theannular flange 300 abuts against the annular gear 150 of the planet gearsub-system and the shoulder portion 201 of the one-way clutch 200 with abearing 302. In this way, each planet gear sub-systems 102 is securedinside the cylindrical casing 154 to ensure the engagement relationshipbetween each small gear 500 and each crown gear 504 of the coupling gearplate 502.

In the sixth embodiment, the front annular gear 150 is integrally formedwith the clutch casing 202 of the one-way clutch 200.

The multi-ratio transmission system 100 of the present invention furtherincludes a central axle 174. The central axle 174 is disposed coaxiallywith the first axis 104, and is inserted to a center through hole 176 ofthe hollowed tube 132 of the setting element controller 130 by relativerotation. The central axle 174 enables the hollowed tube 132 to rotatearound the central axle 174, so that when the rotation controller 133rotates the hollowed tube 132 of the setting element controller 130around the central axle 174, the setting element 124 moves in the axialdirection on the outer circumferential surface 134 of the hollowed tube132.

In the sixth embodiment, the two ends of the central axle 174 aresecured to the bicycle rack respectively, so that the central axle 174is mounted to the bicycle rack and is prevented from relative motion orrotation. In the sixth embodiment, two flat surfaces 178 are formedopposite to each other at each end of the central axle 174. The flatsurfaces 178 are engaged with the external flat surfaces to prevent therotation of the central axle 174. In addition, the flat surfaces 178also provide the space for other components to mount onto the centralaxle 174.

In the sixth embodiment, the multi-ratio transmission system 100 of thepresent invention further includes a one-way clutch 200 disposed outsideof the first planet gear sub-system 102. The one-way clutch 200 abutsagainst the annular flange 300 of the cylindrical casing 154 with thebearing 302 and the front annular gear 150. In the sixth embodiment, theone-way clutch 200 includes a clutch casing 202 and multiple pin sets204. The clutch casing 202 is roughly a cylindrical component formedwith an inner axial end (not numbered) and an outer axial end (notnumbered). The inner axial end is installed onto the front annular gear150 and is located inside the cylindrical casing 154. The outer axialend is located outside of the cylindrical casing 154.

A through hole 208 is formed at the center of the clutch casing 202, andis configured to be coaxial with the first axis 104. The rotationcontroller 133 of the setting element controller 130 is rotatably fittedand supported in the through hole 208. The cross-section shape of thethrough hole 208 is formed corresponding to the rotation controller 133and the shape of the hollowed tube 132 installed on the rotationcontroller 133. This belongs to the common means of those who skilled inthe art, therefore it is not described in detail herein. A fact worthmentioning is that a bearing 210 or other components with similarfunctions are disposed between the rotation controller 133 and thethrough hole 208 for steadily and rotatably supporting the rotationcontroller 133 of the setting element controller 130 and the hollowedtube 132.

An annular protrusion 212 is formed on the outer axial end of the clutchcasing 202, and is formed coaxially with and surrounding the throughhole 208 for coaxially supporting a sprocket 214. Multiple pin-fittingholes 216 are formed on the annular protrusion 212. In the sixthembodiment, six pin-fitting holes 216 are formed on the annularprotrusions 212, but the number of the pin-fitting holes 216 is adjustedaccording to different needs. Preferably, the pin-fitting holes 216 areformed on the annular protrusion 212 in the circumferential directionwith the same angular interval between every two adjacent pin-fittingholes 216. Each pin-fitting hole 216 is formed with a first section 218and a second section 220, in which the first section 218 has a largerdiameter than the second section 220. A shoulder portion 222 is formedbetween the first section 218 and the second section 220. A pin set 204is fitted in each pin-fitting hole 216.

Each pin set 204 includes a housing 224 which is shaped as a hollowedcylinder and a pin 226 which is movably placed inside the housing 224. Aspring 228 is placed between the housing 224 and the pin 226 in such amanner that its inner end abuts against the shoulder portion 222 and itsouter end abuts against a flange of the pin 226. With the flexibility ofthe spring 228, the spring 228 pushes the outer end 230 of the pin 226outside the housing 224, and further engages the outer end 230 of thepin 226 with the engaging holes 232 formed on the sprocket 214. In thisway, the one-way clutch 200 engages with the sprocket 214 to rotatetogether therewith.

With the flexibility of the spring 228, the pin 226 retracts back intothe casing 224 when the outer end 230 of the pin 226 is under internalstress. Under this condition, the inner end of the pin 226 is fittedinside the second section 220 of the pin-fitting hole 216 of the housing224, thereby avoiding interferences between the components.

Multiple engaging holes 232 are formed on the sprockets 214. Theengaging holes 232 are distributed along a circle, which is coaxial withthe first axis 104, with equal angular interval therebetween. Eachengaging hole 232 has a front end and a back end (both not numbered) inthe circumferential direction. The back end has a flat surface, whichabuts against the outer end 230 of the pin 226, for transmitting theforce. When the sprocket 214 rotates forward, the back ends of theengaging holes 232 also rotate forward with the pins 226, therebytransmitting the torque and the rotation motion to the multi-ratiotransmission system 100 of the present invention. On the other hand, thefront end of the engaging hole 232 is an oblique surface, which servesas a cam. The front end of the engaging hole 232 can guide the outer end230 of the pin 226 to the outside of the engaging hole 232 when it comesinto contact with the outer end 230 of the pin 226. Hence, when thesprockets 214 rotates backward, the pin 226 would not transmit thetorque and the rotation motion to the multi-ratio transmission system100 of the present invention due to the oblique surface of the front endof the engaging hole 232. In this way, the one-way clutch 200 transmitsthe torque and rotation motion in one direction only.

In the sixth embodiment, the multi-ratio transmission system 100 of thepresent invention further includes a shift cable connector 234. Theshift cable connector has an inner axial pin 236 for inserting into andconnecting with a connecting hole 238 of the rotation controller 133 ofthe setting element controller 130. The connecting hole 238 is formedeccentrically to the first axis 104, in this way, the shift cableconnector 234 can rotate the connecting hole 238 to rotate around thefirst axis 104, and further drives the hollowed tube 132 of the rotationcontroller 133 to rotate around the first axis 104, thereby shiftingbetween different gear ratios.

A shift cable (not shown) is installed onto the shift cable connector234. The shift cable is the shift cable commonly seen on any bicycles,which is connected with a lever installed on the bicycle. When the usershifts the lever, the shift cable is then pulled by the lever andfurther rotates the setting element controller 130 through the shiftcable connector 234.

In addition, an outer axial pin 240 is disposed on the shift cableconnector 234 opposite to the inner axial pin 236.

A shift-guiding component 242 is inserted and connected to the centralaxle 174. Especially, an insertion hole 244 is formed at the center ofthe shift-guiding component 242, in which the two sides of the insertionhole 244 are formed as two flat walls 246 for abutting against the flatsurfaces 178 of the central axle 174, so the relative rotation betweenthe two is prevented. In addition, a circular guiding groove 248 isformed coaxially with the first axis 104 on the shift-guiding component242. The circular guiding groove 248 extends in a range of angles alongthe circumferential direction, in which the range of angles iscorresponded to the range of predetermined angles for the rotation ofthe hollowed tube 132 of the setting element controller 130.

The outer axial pin 240 of the shift cable connector 234 is insertedinto the circular guiding groove 248 to move along the circular guidinggroove 248. When the user pulls the shift cable connector 234 throughthe shift cable, the outer axial pin 240 then moves along the circularguiding groove 248, thereby achieving the shifting between differentgear ratios. Herein, a fact worth mentioning is that the two ends of thecircular guiding groove 248 serve as the stopper of the outer axial pin240 to prevent the outer axial pin 240 from moving out of range.

A restoring spring 250 is disposed between the shift-guiding component242 and the rotation controller 133 of the setting element controller130. The restoring spring 250 can server as the restoring force of thesetting element controller 130 after the gear shifting, in which thesetting element controller 130 is pulled by the shift cable. In thesixth embodiment, the restoring spring 250 has two side ends 252, whichare inserted into the insertion hole 254 firmed on the rotationcontroller 133 and the insertion hole 256 formed on the shift-guidingcomponent 242 respectively.

Although the present invention has been described with reference to thepreferred embodiments thereof, it is apparent to those skilled in theart that a variety of modifications and changes may be made withoutdeparting from the scope of the present invention which is intended tobe defined by the appended claims. Any equivalent structures in the samefield or other related fields achieved with the description and figuresof the present invention should be considered within the scope ofprotection of the present invention.

1. A multi-ratio transmission system with parallel vertical and coaxialplanet gears, comprising: a plurality of planet gear sub-systems, beingcoaxially disposed in series along a first axis, each of said planetgear sub-system comprising: a sun gear, being coaxially disposed alongsaid first axis, wherein said sun gear rotates around said first axisoptionally; and at least one planet gear, being coaxially disposed alonga second axis which is vertical to said first axis, wherein said atleast one planet gear rotates around said second axis; a couplingassembly disposed between every two adjacent said planet gearsub-systems so as to transmit rotation of said planet gear of the formersaid planet gear sub-system to said planet gear of the latter saidplanet gear sub-system; a setting element disposed corresponding to eachof said planet gear sub-systems, wherein said setting element optionallymoves in the direction of said first axis so as to optionally engagewith said sun gear of said planet gear sub-system; a setting elementcontroller, having a hollowed tube disposed coaxially with said firstaxis to rotate around said first axis within a range of predeterminedangles, wherein said hollowed tube has an outer circumferential surface,and a cam groove is formed on said outer circumferential surface in thecircumferential direction corresponding to each of said setting elementof said planet gear sub-system, thereby allowing said setting element tooptionally move along said first axis and to optionally engage with saidsun gears of said planet gear sub-systems; an annular gear engaged tosaid planet gear of at least one of said planet gear sub-system, whereinsaid annular gear is installed onto a one-way clutch; a cylindricalcasing enclosing said planet gear sub-systems, wherein said annular gearis secured at a front end of said cylindrical casing; a sprocket,installed onto said one-way clutch, wherein an external transmissionsystem is connected with said sprocket to drive said planet gearsub-systems to rotate through said one-way clutch and said annular gear;and a central axle, being disposed coaxially with said first axis,wherein said central axle is inserted into a center through hole of saidhollowed tube of said setting element controller by relative rotation,thereby enabling said hollowed tube to rotate around said central axle.2. The multi-ratio transmission system with parallel vertical andcoaxial planet gears according to claim 1, wherein said second axes ofsaid planet gears of said planet gear sub-systems are configured to beparallel to one another.
 3. The multi-ratio transmission system withparallel vertical and coaxial planet gears according to claim 1, whereinsaid sun gear of each of said planet gear sub-systems includes an outergear, which is a bevel gear, and said planet gear of each said planetgear sub-system is a bevel gear engaging with said outer gear of saidsun gear.
 4. The multi-ratio transmission system with parallel verticaland coaxial planet gears according to claim 3, wherein said sun gearfurther includes an inner gear, and said setting element is a crowngear, which optionally engages with said inner gear of said sun gear. 5.The multi-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 1, wherein said sun gear of each planetgear sub-system includes an outer gear and an inner gear which arecoaxially connected to each other, said outer gear is located at theouter side of said inner gear and is a bevel gear, said planet gear ofsaid planet gear sub-system is a bevel gear, which is engaged with saidouter gear of said sun gear, and said setting element is a crown gear,which optionally engages with said inner gear of said sun gear.
 6. Themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 1, wherein each planet gear sub-systemhas two planet gears, which are disposed opposite to each other.
 7. Themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 1, wherein said coupling assemblyincludes: two pulleys, connected to said planet gears of said twoadjacent planet gear sub-systems respectively, and being rotated insynchronization with said planet gears respectively; and a belt trainedaround said two pulleys so as to connect said two pulleys.
 8. Themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 1, wherein said central axle has twoends, said two ends of said central axle are secured on a bicycle rackrespectively.
 9. The multi-ratio transmission system with parallelvertical and coaxial planet gears according to claim 8, wherein two flatsurfaces are formed opposite to each other on each end of said centralaxle, said two flat surfaces of said central axle are engaged with twocorresponding flat surfaces of said bicycle rack to prevent relativerotation between said central axle and said bicycle rack.
 10. Themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 1, wherein said setting elementcontroller further includes a rotation controller, said rotationcontroller is installed onto an end of said hollowed tube so as tooptionally rotate said hollowed tube in said range of predeterminedangles.
 11. The multi-ratio transmission system with parallel verticaland coaxial planet gears according to claim 1, wherein said settingelement includes a hollowed cylinder, a plurality of teeth is formed ona side end of said hollowed cylinder, and said hollowed cylinder isdisposed coaxially with said sun gear of said planet gear sub-system insuch way that said hollowed cylinder moves along said first axiscorresponding to said sun gear, thereby allowing said teeth tooptionally engage with said sun gear; said hollowed cylinder includes acontrol pin, wherein a free end of said control pin is inserted intosaid cam groove to move along said cam groove.
 12. The multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to claim 1, wherein an outer thread is formed on a sidecircumferential surface of said annular gear, an inner thread is formedon an inner circumferential surface of said cylindrical casing at afront end thereof, and said inner thread is engaged with said outerthread so as to secure said annular gear at said front end of saidcylindrical casing.
 13. The multi-ratio transmission system withparallel vertical and coaxial planet gears according to claim 1 furtherincludes another said annular gear, wherein the other said annular gearis secured at a rear end of said cylindrical casing opposite to saidfront end, said annular gear and the other said annular gear are engagedwith said planet gear of a first and a last planet gear sub-systems ofsaid plurality of planet gear sub-systems respectively; wherein saidfirst and said last planet gear sub-systems further include atransmission gear, which is coaxially connected to said planet gear toengage with said annular gear.
 14. The multi-ratio transmission systemwith parallel vertical and coaxial planet gears according to claim 13,wherein the other said annular gear has an axial end, a flange isinwardly formed at said front end of said cylindrical casing, said otherannular gear is rotatably fitted at said rear end of said cylindricalcasing by abutting said flange of said cylindrical casing against saidaxial end of said other annular gear.
 15. (canceled)
 16. (canceled) 17.The multi-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 14, wherein an outer thread is formed ona side circumferential surface of said annular gear engaging with saidplanet gear of said first planet gear sub-system, an inner thread isformed on an inner circumferential surface of said cylindrical casing ata front end thereof, and said inner thread is engaged with said outerthread so as to secure said annular gear at said front end of saidcylindrical casing.
 18. The multi-ratio transmission system withparallel vertical and coaxial planet gears according to claim 1, whereineach planet gear sub-system includes an annular base, a circular wallstructure is formed on said annular base surrounding said settingelement and said planet gear of said planet gear sub-system while beingdisposed coaxially with said first axis; wherein a hole is formed onsaid annular base for rotatably fitting and supporting an axle of saidplanet gear.
 19. The multi-ratio transmission system with parallelvertical and coaxial planet gears according to claim 18, wherein eachsaid annular base of said planet gear sub-systems is formed with twoaxial ends, and said axial ends of said annular bases are abuttedagainst each other in the direction of said first axis.
 20. Themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 19, wherein at least one axial groove isformed on an outer side surface of each said annular base, said axialgroove extends from one of said axial ends of said annular base toanother said axial end thereof for tightly fitting a securing rod insideso as to prevent relative rotation between said annular bases.
 21. Themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 10, wherein said rotation controller isinstalled onto a shift cable connector for connecting to a shift cable,said rotation controller and said hollowed tube installed onto saidrotation controller are driven to rotate around said first axis bypulling said shift cable.
 22. The multi-ratio transmission system withparallel vertical and coaxial planet gears according to claim 21,wherein a connecting hole is formed on said rotation controller forinserting an inner axial pin of said shift cable connector.
 23. Themulti-ratio transmission system with parallel vertical and coaxialplanet gears according to claim 21 further includes a shift-guidingcomponent inserted and connected to said central axle, wherein acircular guiding groove is formed coaxially with said first axis on saidshift-guiding component, said shift cable connector has an outer axialpin which is slidably inserted into said circular guiding groove;wherein said circular guiding groove extends for a range of angles inthe circumferential direction corresponding to said range ofpredetermined angles of the rotation of said hollowed tube of saidsetting element controller.
 24. The multi-ratio transmission system withparallel vertical and coaxial planet gears according to claim 23,wherein an insertion hole is formed at the center of said shift-guidingcomponent, and the two sides of said insertion hole are formed as twoflat walls for abutting against said flat surfaces of said central axle,thereby preventing relative rotation between said central axle and saidshift-guiding component.
 25. The multi-ratio transmission system withparallel vertical and coaxial planet gears according to claim 1, whereinsaid one-way clutch includes: a clutch casing integrally formed withsaid annular gear, wherein said clutch casing has an annular protrusionfor installing said sprocket, and at least one pin-fitting hole isformed on said annular protrusion; and at least one pin set fittedinside said pin-fitting hole, wherein said pin set includes a pin, whichis constantly pushed outward by a spring to engage with one of aplurality of engaging holes formed on said sprocket, and is retractedfrom said engaging hole by an external force.
 26. The multi-ratiotransmission system with parallel vertical and coaxial planet gearsaccording to claim 25, wherein said engaging holes of said sprocket aredistributed along a circle, which is coaxial to said first axis, withequal angular intervals in between every two adjacent engaging holes;wherein each engaging hole has a flat surface and an oblique surfaceopposite to said flat surface, said flat surface is abutted against saidpin to transmit force in a given rotation direction, said obliquesurface serves as a cam and guides said pin outside said engaging holeupon contact to avoid force transmission in a rotation directionopposite to said given rotation direction